QUADRASTEER! GM Parasitic Battery Drain from the FACTORY? (Part 1)

This rare beautiful GMC Sierra QUADRASTEER apparently came with a defect from the factory. According to the owner, it has always drained the battery during extended periods of sitting.
In 20 YEARS it has been to countless GM dealers and other shops in efforts to solve this annoying problem!
Let's dive in and use our tried and tested methods for pinpointing this elusive parasitic battery drain. The owner loves his truck, and wants it to be PERFECT!!
ASTRO AI DVOM:
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ZEEWEII 2 CHANNEL POCKET OSCILLOSCOPE: ****$30 OFF!!***
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Enjoy!
Ivan

[@russellstephan6844]

I purchased a used C1500 20 years ago. It also had a current draw. I'd occasionally attempt to find the source. But, since the vehicle is not a daily driver, I just put a knife switch on the battery along with a smart trickle charger. Fast forward 18 years and while under the dash to do some other work, I discovered an aftermarket relay spliced in the wiring system. There it is! I removed the do nothing relay and the draw is now gone. So, I eventually get around to fixing stuff. It may take a decade or two, though. ;-)

[@chrissmith7655]

Hi, part2 ,part2, part2, ASAP please. Many thanks, from UK.

[@Garth2011]

This is probably the very first customer vehicle I have seen on PHAD where the owner has had the vehicle that long and keeps it so nice and clean etc. BTW, this truck is a keeper...I'd be going to salvage yards once a week/month collecting the most obvious parts needed to keep it factory perfect. Unfortunately, the Quadrasteer system is no longer supported, it was made by Delphi in the day. The Suburbans even had quadrasteer but only the 2500 models I believe.

[@scrappy7571]

Those auto hvac modules of that era are known to take up to several hours to go to sleep. Pretty sure there were bulletins for this. Been there done that. EDIT found it The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI. Condition/Concern: Additional detail beyond TSB 02-01-39-007A. Vehicle may have a concern with the battery going dead overnight. The draw can be from 40 to 60 mA. This is due to the HVAC control head staying "awake". Further diagnostics may show that the draw is reduced to approx 5 - 9 mA with either the front HVAC controller unplugged or HVAC fuse B pulled. Disconnecting (& reconnecting) the battery may result in the draw being gone until the next key cycle. The rear HVAC head is unrelated to this issue. Recommendation/Instructions: A draw of approx. 60 mA for 2.5 to 3 hours after vehicle shutdown is normal. The time varies with ambient temperature. However, this should NOT be enough to drain the battery. DO NOT replace the HVAC control head for a draw of 60 mA (approx) or less.

[@stevewhite3424]

Amazing what a bit of research can dig up! 😊

[@scrappy7571]

@@stevewhite3424 I worked on these at the dealer when new, what's amazing is the useless crap stored in my head from 20 years ago.

[@stevewhite3424]

@@scrappy7571 😂😂😂😂😂

[@gr7485]

A quadrasteer GMC truck...thats a new one for me...never heard of it before.

[@user-vd4kj3gs4s]

This is my truck. The problem has been there for 18 years. Nobody could find it not even dealers, The truck is absolutlry perfect or I would not have put a supercharger on it. She is a beast. The wiring was done to perfection, The extra relays are for the fans and the plow. Nobody at GM could figure it out The original owner (my best friend) did not want to send it back on lemon law. The truck is a legit runner with the super charger. You can pick on anything yu want, but nobody has taken care of her like I have. It is a heavy half ton (3/4 chassis) because the rear end is down graded due to weight restriction.

[@hikerJohn]

Trailer Break Controller should be on the ignition and not hot with the key off

[@gar24407]

Ivan is like, finally a worthy challenger!!! A 20 year undefeated truck has met its match🤣😂.

[@mikemurphy7519]

I am writing this as the video plays. A 175ma draw will not kill a 50 amp-hour battery to the point where it won't crank the car until about 12 days. The owner said it dies in 3 days. With that said, this is an issue, but might not be the only cause. When you unplugged the control unit the amperage did not drop down to the 35ma like it did when you pulled the fuse. I am going to guess the trailer unit is tapped into the hvac power wires with one of those blue taps.

[@ronwade2206]

Yup, ye old Scotch-Locks! I loved 'em when I worked in auto electrical, job security for sure!

[@willemstreutgers1154]

Mike i give you the benefit for this good "guess"

[@shagsshag149]

That’s my guess also tapped in to trailer to hvac,as if this car had a draw for 20yrs😂

[@Dirtyharry70585]

The owner should have the trailer brake on switched 12v

[@tomtke7351]

E X A C T L Y my thoughts too!

[@heny3231]

Great video, just wondering if the fuse that is supposed to control only HVAC module has actually been utilsed for the aftermarket trailer module, which is why it dropped immediately when the fuse was pulled but not when HVAC disconnected?

[@craiggoodwin9704]

Interesting thought! Appreciate your comment. 🙃🙂

[@ecaparts]

Good point. I totally agree the 100+mA of current to power the Trailer Brake module may be tapped off that HVAC fuse. You can see a forbidden aftermarket wire on top of the fuse box, near the fuse. Also Ivan didn't find ANY OTHER FUSES with a VOLTAGE DROP. This is important because the Trailer brake module draws almost 3 times the power of the HVAC module, and should have been easily found if another fuse was involved...

[@stevewhite3424]

Interesting except the customer states that the parasitic draw was there before the truck was ever modified. As another sharp eyed commenter found, there is actually a t s b for this very issue.

[@mattbrown5511]

Can't wait for the Part 2. Seem that the trailer brake controller is tapped into the HVAC system somehow by the symptoms it is showing.

[@oldbatwit5102]

The size, shape and weight of a modest apartment. Check the lighting in the guest bathroom.

[@mikechiodetti4482]

On to part 2. Can that trailer brake be wired to the ign switch? Hopefully there's a relay that the control can be directly wired into. I also hope the control wasn't wired into the BCM.

[@lustfulvengance]

"The owner wants it all original so we're not going to do any Russian hacks" 🤣🤣🤣🤣🤣🤣🤣 You're the best Ivan! The fact that you know how systems work well enough to know how to temporarily (permanently in some instances) bypass something or rig something up to make it work is a testament to your genius!

[@josephwash109]

This reminds me of a South Main Auto video where Eric O. determined that the foam on the doors inside the HVAC box had worn off, causing an issue with the HVAC system actuators. I don't think the module itself has a failure, it's simply trying to carry out a command to see a specific voltage feedback from an actuator potentiometer after the ignition power is turned off. If this Sierra has had the problem since it was new, the HVAC box may have been assembled improperly.

[@dudleydeplorable5307]

Years ago, I had to diagnose a power draw issue. It was a first generation pad cell phone charger. You could put a coin on the pad and it would get too hot to touch. Enough said...

[@kerrylewis2581]

Your reputation is bringing in some interesting projects

[@melissathompson7229]

Glad you'll actually get to the bottom of it instead of blaming the aftermarket equipment. Even though the draw was there stock, most mechanics will still blame that instead of doing an amp draw test

[@pinecone01]

You know it's gonna be good when there's a "part 1" in the video title!

[@skysurferuk]

22:05 Totally agree with you, Ivan, those picks are the most handy tool I have. Great content, as usual! 👍

[@tomtke7351]

I get it! You "go the distance" to sort thru findings & facts..... ALTHOUGH it's a pain searching, and reaching, and contorting your body... AND maybe breaking panels and connectors. You need to be UPFRONT with customers that you are MORE THOROUGH than most shops can afford to be and, so, you are more valuable = more expensive. Not PEEFECT, but more thorough!! And great advice for DIY'ers who have more time...

[@russellhltn1396]

Owner: NO ONE can find this parasitic draw. PHAD: Challenge accepted.

[@markt5426]

Thanks Ivan, Yet again, enjoyed watching you expertise working on all kind of problems. 👍

[@Flowtester1]

I knew GM made these quadra steer trucks but i had never seen one.

[@85rx7se]

Can't wait to see part 2 ... What I think you should do is check and wire the trailer brake controller to get power when the ignition is in the Run Position. For the HVAC unit, wire it so that is connected to 12V Accessory Power .. That should fix everything without needing a new track control head

[@MadmanJimbo]

I would check the Schosch chime. Having fixed 30+ of them for parasitic draw

[@ghettsumm7949]

Based on the age of the truck, that HVAC module could easily be found in the local junkyard for very little $$$. Great diag Ivan. The dealer should have caught this one.

[@on-site4094]

U gotta love it when u have enough room under the hood for a second battery

[@topher8634]

It's a nice feature but it looked like the cables were close to the A/C lines. Vibration would rub a hole through them.

[@colmmccabe2998]

Keep them videos coming ivan i look forward to watching them😊

[@kevincampbell8298]

Was looking at my brothers 15 Jeep yesterday. Same a 70mA draw. 2 batteries. Ugh Going back Friday.

[@craiggoodwin9704]

Ivan, a lot of added wires there. Been looking at that pocket oscilloscope since your last video or two. Looks very handy! Thanks for Sharing! 🙂

[@lovetolearn5253]

Im wondering if the trailer brake is wired in the hvac fuse. Cant wait until part 2. I love diagnostic videos. Seriously they're my favorite thing to watch. When other shops in my area complain about the electrical issue I'm saying I'll take the worst of the worst. I really do enjoy it.

[@mkilptrick]

My favorite video stop. Thanks Ivan.

[@tomtke7351]

you and I agree (along with a former FAA certified mechanic) that Harbor Freight has SOME good 'stuff!' But Buyer Beware!

[@topher8634]

I've lost a lot of meat on my knuckles from Harbor Freight.

[@user-nq4zt4xu2t]

Thanks for your content, Ivan! Hope I’ll survive and be able to watch coming part 2 of this amazing diagnostic. It’s nice to take a break watching your videos and get rid from permanent sadness for a while. What a bad idea was get to university in Rostov And sorry for my grammar

[@jgeorges3061]

IVAN, Thanks for sharing really enjoyed this one waiting for part 2. cheeeeers

[@richardmikolajczakjr5016]

At 22:16 while pulling out hvac control head it sounded like IVAN passed a little wind listen closely even you Ivan 😂we are all human at the end of the day a little gas breaks up the suspense

[@JoseSilveira-newhandleforYT]

Beautiful and carefully preserved machine, with a mean sound - I like it! A parasitic draw on a vehicle with few modules, and there's more than one Part! This should be good :-) Yep, confirmed - there's a gremlin hiding somewhere, maybe on one of the aftermarket add-ons, or on the splicing to power them (that TBCM alone, has a suspicious behavior).

[@cyberslacker5150]

You said"CURVE BALL". I'm thinking that either, another module is waking up the HVAC module or yes, the HVAC module and the trailer module is drawing current, but since the batteries have been discharged often, then they don't have capacity anymore. Batteries tend to get damaged and lose most of their capacity when they're deeply discharged. In that case you would need new batteries. Evan at 175 milliamps, two good batteries should stay charged well over a week. Also that Cell phone charger tends to stay on. That's a draw. You should unplug that too, see what happens.

[@paulv7217]

Looking forward to the test drive 😎

[@NoWr2Run]

I like your battery bolt holder, LOL.

[@firzen0000]

That thing is mint! Absolutely fantastic condition. I'm feeling lightheaded just looking at it. 😍

[@richardnilsen2]

A good project for someone who can figure out anything Interesting content 👍

[@raymondjacobs8335]

Ivan, I remember back 70's - 90's maybe, GM had the fan motor "On" at all times, really low but always on. when the car was started.

[@jtjones4727]

Pretty sweet truck, and it's mint. I didn't even know you could get a 1500 series with Quadrasteer. You would think they would have a programming update for those HVAC units, I'm pretty sure it's at least a known issue within GM.

[@Mr2004MCSS]

A guy I knew had a 2002 1500 with the Quadrasteer. He bought it new and had put a lot of money down on it so that in 2003, he only owed around $12,000 on it. He decided he didn't want payments any more so he wanted to trade me his truck for what he owed and have me give him my paid off 1998 Silverado 4x4. I ended up not doing the trade but sometimes wish I had. It was a fully loaded nice truck. I still have my 98 which I also bought new.

[@baxrok2.]

Thanks Ivan!

[@petepeabody8905]

How come you have all the fun???? Nice job so far Ivan.. Very cool truck too........Pete

[@user-vd4kj3gs4s]

I forgot to say that this truck is THE truck that was used in Cleveland and Detroit for the debut. I have had 2015 and 2014 GNC;s that cannot hold a candle to it. She is a bad bitch. I take of my cars I take care of my wife. The extra battery was added for the draw and the plow usage. I know somebody said the decals look JANKY. So what, I have only positive comments. This truck hauls my car trailer with zero problems. I drove 4 hours each way because I knew Ivan would find the problem. He is the best at what he does. Good vibes all around. Look out for the part 2.

[@thegmguy1]

I own an 03 Sierra quadrasteer as well with that exact same brake controller and it does take it quite awhile to shut down. I’ve also noticed odd things triggering it to wake up like opening the door or of course bumping the brake pedal by accident. Never had it kill my battery though.

[@nonamegiven7594]

Love your videos.

[@omdcarsandairplanes]

Sweet truck! I love these.

[@athhud]

My money was on the instrument panel. I had a .2amp draw on my ‘03 2500 HD that really left me scratching my head. I isolated the problem to the instrument panel, but couldn’t for the life of me find anything actually wrong with it. Around that same time, Eric O posted a video where he diagnosed a similar problem. Of course he sent the cluster off to be fixed, but I am too cheap for that... Fortunately his conversation with board repair guy gave me a clue. Some hot air and flux on the back of the board followed with an alcohol scrub/ultrasonic cleaning eliminated the parasitic draw. I still never actually identified the short, even with a magnifying lens on my phone and the zoom maxed out. It was just invisible/microscopic “EPA friendly” lead-free solder corrosion that shorted out a couple of the traces on the back side of the board. An IR camera would have probably tracked it down immediately, but I haven’t found myself really needing one YET. I was just shocked that .2amps could be pulled through a short that I couldn’t find (I am not exactly a circuit board noob). A Louis Rossmann alcohol evaporation test would have probably worked too, but frankly it was easier to just go the belt and suspenders route of cleaning the entire board.

[@dustcommander100]

That rear steering blows my mind. I got behind one of those trucks once and could see the axle was capable of being steered. To my knowledge, it was the only one I've encountered. I have a friend that works for the GMC dealer and talked about it with him. There is a big old spring that centers the rear steering when it's not active or if it has a fault. Interesting, but not something I'd want. It amazes me the truck is so nice, and yet is used as a snowplow! Can't wait to see the rest of this one! I wonder why the brake controller is always powered up - maybe there is a good reason? Can't remember how mine is wired, but it's much simpler - as is the rest of the truck.

[@larrybe2900]

Is there a backup camera installed?

[@cigarsgunsandgasoline8032]

yeah plowing with that truck is cringe... especially a rare Q/S! Why people plow with anything under a 2500 makes no sense... 1500 and lower can't take the abuse of plowing like a HD truck!

[@adequatedust]

You pulled the fuse and went to sleep. Pull the module and it did not go to sleep and the brake controller stayed on. Seems like something (brake controller maybe) is wired into the line from that fuse.

[@kc6nfv746]

Thank you for the video

[@zenithperigee7442]

@Pine Hollow Auto Diagnostics, hi Ivan! That's a really nice truck! It wasn't easy to monitor but I noticed that the trailer brake controller didn't seem to illuminate until after the @21:00 mark where you proceeded to put in the key, press on the brake pedal and pull the gear lever down & the controller displayed fluctuating digits. From then on it seemed to remain "active". I wonder, does it have a 10-minute timer, seems excessive... Anyway, interested to see the "curve ball". I actually read up on a problem like this and someone making their own "fix" related to the "climate control unit". I wasn't looking for that but an explanation for what "ECAS" represented.

[@billsmith5166]

Considering all the dollars in electronics that you use it's funny to see that ancient meter. It's so old that the probes look dull.

[@ablackformula]

I have the same brake controller in my 2004 chevy 2500. It goes to sleep but wakes back up when you open a door. It has no inputs to tell it a door is open -- i believe its a voltage sensing circuit in the controller. So as your testing and opening doors or paralleling/isolating batteries, you may be inadvertently keeping the brake controller awake.

[@calholli]

I'd be all for putting both the trailer module and the Hvac memory fuses to key power, rather than direct to battery like they are... If this was my truck. That's the price of wanting everything to be "clean" though --- you end up buying an expensive module when there is an easier way to fix it. Part 2 should be fun though.. Gotta love the curve balls.

[@Walczyk]

Whoever installed the trailer tapped the trailer brake modules ground into the hvac shut off signal wire or possibly cut it. I’m sure Ivan will fix the installation and ignoring the wire repair it will be no parts required

[@AP9311]

I have seen some quatrasteer has a draw from the bcm on those trucks. Maybe worth a check on those. Those are hard to diagnose. But great video Ivan!!

[@garybowles9062]

That trailer brake control unit may be supposed to be wired to ignition on power; may not have a sleep option; can correct that issue very easily

[@davyarthurs]

The Trailer Brake Module didn’t go to sleep, it lost its power because you pulled the HVAC fuse - place your bets!

[@HoboJoeGarage]

Depending on how they wired that controller it can play a roll in the issue. Those trucks came with a factory harness (when equipped with trailer tow package) and a piggyback harness that would get spliced into the aftermarket trailer brake controller.

[@mattcat231]

Man that truck is a beauty!!!!!!! AND a quadrasteer!!!!!!!

[@MrOverstuffedcow]

My guess, blend door actuator stuck and trailer brake wired to constant instead of accessory.

[@Frank-pv1hp]

Hey Ivan, I'd like to qualify your statement about the thermal imager use for parasitic draw testing. I've found quite a few Honda and Acura HFL draws that are right about 240mA, (a dead giveaway for a HFL failure) by using the thermal imager. On some Hondas the HFL is in the dome light bezel area, on some Acura's it's in the rear of the center console. Here's the big if. You can see the heat from that draw IF the ambient temp of the interior is low enough. Usually that would be around 55 degrees or less. In the later part of spring and summer time, the thermal imager won't be nearly as helpful.

[@jeffryblackmon4846]

"Current owner?" Was that an intentional joke? I like it! Part 2 will be interesting. Thanks once more for a great video, Ivan!

[@MrKingdavis13]

I would pull the fuse again to see if it shuts off the trailer brake controller since they might have pulled power from that circuit and the two systems are interacting to keep each other alive. Is that the curve ball?

[@billziegmond4943]

Very interesting my friend.

[@jessicav2031]

2003 GM truck with a draw? This is one of those cases where you have to go straight to one thing before you even bother doing testing. The cluster draws are almost always intermittent on the scale of days. I'd have the guy take out the cluster and see if it still happens before even bringing it in. The cluster problem is so common that we have had two of these vehicles in my immediate family and both had it (one had even had the cluster replaced by the dealer and the second one also failed). Then at one point I was visiting my cousin and noticed his was sitting sadly in the back of the driveway, I peered in the window, and the cluster was on. Turns out he had tried to find the draw, failed, and given up. Scrubbed the back of the PCB and scraped around the vias, problem solved once again. I also went down the road of thinking one of these was the HVAC module because it wakes up from time to time and I kept seeing draws on that fuse (same symptom as you are seeing here, identical HVAC module). It was not the problem. Rebuilding the cluster fixed it. I was fixated on the HVAC module until I saw the speedometer move while the truck was off. Is it cheating if you've been tricked before by the exact thing in the video?

[@geoepi321975]

When you talk about parasitic drain Ivan it comes to mind thevenins theorem ..

[@autotek7930]

I had a 4ws bmw the other day. The rear suspension components are extremely weak on those. Barely scratched the rim and it bent most of the links

[@landonthompson5604]

My 03 Chevrolet silverado 1500 had a really odd backfeed noise back into the factory head unit. Fluffy the rat had chrewed some of the harness for the Bluetooth/hands-free system, granted i had to almost remove my internal skeletal body to find the feast but I'm happier now especially since I don't have to listen to the sound and my wife griping

[@keltecshooter]

That's a fancy brake controller for sure, is it tied into the data line for some reason ?

[@timothycampbell2508]

It’s the BCM there’s an open recall. BCM/ECU reads ignition still on even though it’s off and key is removed. However it absolutely will still allow you to lock and unlock as normal. I have a 2003 Tahoe 5.3 I’ve learned by leaving a fm transmitter in the 12V socket and I will work my ignition key back n forth a couple times until it’s turns off with key. Then I know it’s shut down the BCM and won’t draw. You can take to dealer for free BCM replacement or buy your own and have a locksmith program it.

[@Ram14250]

Great video, but man, that's a lot of aftermarket equipment. ... lots of splices in the factory wiring. Why does he want that wireless charging pad on all the time? 🤔 Interesting to see what it might be.

[@wernerdanler2742]

Looks like he might have wired it to constant power instead of the ignition.

[@Ram14250]

@@wernerdanler2742 Power draw 100% of time.

[@shadymaint1]

I had a similar HVAC module in a Hummer have the same issue.

[@bombardier3qtrlbpsi]

I know you want to tear the module apart and fix it 😆😆 I'll give you 👍👍 I won't tell no one. Just pay me a silent fee😃 Fantastic Job

[@ehsnils]

Just hope that the part number is the correct one for that vehicle. The wrong part number already from factory can result in a never-ending problem.

[@johndesaavedra1040]

These trucks were also notorious for having a wiper park switch hang up and slowly drain the battery.

[@hpelisr]

That trailer brake needs investigated. Stay on it Ivan.

[@mark98070]

I have the same Tekonsha trailer brake controller. Mine goes to sleep in just a few minutes

[@davidgrisco1939]

I have that same HVAC module in our 2003 Trailblazer and it was replaced under warranty. But it has a defect once again with the rotary knob contacts (it's digital) that are not linear, the temperature values jump when turned. So instead, I use the steering wheel switches.

[@PileOfEmptyTapes]

That's the classic mechanical encoder with bad contact issue. Often the (nonconductive) silicone grease used on the shaft for a more damped feel will seep out onto the contact area over time. Basically a NPR repair if you don't count a cotton swab with isopropyl alcohol and perhaps a bit of sealing contact cleaner. The older ones tend to be quite easy to disassemble and clean, newer ones less so.

[@davidgrisco1939]

@@PileOfEmptyTapes maybe, Ill try that...now if only I could find the right foam to replace under my driver seat cushion. I'm @313k miles, looking for at least 400k!

[@peto22]

I have to say I love European trailer brakes. There is only a telescopic drawbar that uses mechanical brakes. If the trailer has brakes, they will work on any towing vehicle.

[@stevewhite3424]

Nothing European about that style of trailer braking. They are called surge brakes and are used everywhere.

[@windward2818]

The customer added another battery too increase capacity? I think it was an attempt at increasing stand-time (time between using the vehicle), but the problem is you cannot just add another battery unless the vehicle was designed for two batteries and came from the factory with two batteries. If you need additional battery power to run extra loads that have high surge current, like a large hydraulic snow plow, then the added battery would be deep discharge / start AGM and have its own separate alternator (with integral regulator). If you needed the auxiliary AGM battery to start the vehicle in an emergency you could install a manual combiner (a large switch). Usually the AGM battery has provision to connect jump cables (connected with high DC current Anderson connectors with a sealed rubber boot(s)) with a large manual switch to enable power (like a large sealed boat main bus power DC switch). So if you want to jump a vehicle you can use the aux battery and not the starting battery. The aux and main battery systems are separate unless you combine them manually. The manual jump cable switch (on aux BAT+) when off enables direct connection of the jump cables to the dead battery posts without sparks (no need to try and find a good separate ground). Then you actuate the power switch manually to connect the two batteries. In addition to the jump power manual switch I like to include a marine style DC voltmeter (I like the OLED display versions they are very visible and easy to read) after the switch but before the connector. You can use it to momentarily measure the aux battery voltage with the switch on and cables disconnected to measure battery and charging voltage. You can also use it to measure the battery voltage of the dead battery before enabling power. This is very handy, in that, if the dead battery is very low it may be damaged (shorted plate, cracked case, etc.) and you may not want to attempt a jump. Also, the voltmeter can be used to measure the charging voltage of the dead vehicle after it is started and the power switch turned off. This is also handy because if the battery is not being charged (a bad alternator) then you probably do not want to attempt to drive the vehicle, because it will shortly die. You only real viable way to increase battery stand-time is to put in a larger battery (30% greater CCA, with a large V8 should not effect idle speed control), you can either max out the tray, or install a larger tray with new hold downs. Usually, what I find is the Alternator output cable and block return (if not already large enough) is increased from 6 AWG to 4 AWG (on older vehicles, the Fusible Link wire increases from 10 AWG (some times two 12 AWG FL are in parallel like on the Fords) to 8 AWG. The block ground minimum is usually 2 AWG SGX, many times moving to 1 AWG welding cable (which is more flexible than SGX, especially when cold).

[@KGauto_Diagnostics]

I had one really really similar to this on a 03 gm truck. Turned out to be the ignition switch. Kept the hvac alive after key cycle.

[@russellhltn1396]

Good point! Ivan didn't check to make sure the powers and grounds were correct for going asleep. (And in this case, I wouldn't use a test light, but just the meter.) This could also be what's keeping the trailer brake awake. When you have two devices showing similar symptoms, it's probably not two bad units.

[@topher8634]

GM ignition switches have always been an anomaly. Replaced many. I have seen them cause HVAC problems and transmission issues.

[@bobbg9041]

20:13 watch this part agine, look at the transmission oil cool line at the radator the top like looks like it has a pin hole in it or its just a flake of dirt, tell this guy to ck his automatic transmission fulids and look at the black dot by the connector at the radator on the metal line. Top right facing the frt of the truck.

[@titanicfilmsbymark]

Is there something like you in Southern California?

[@hugh007]

I dont own one so I dont know, but it seems all the mechanisms needed may be more to maintain or repair for IMHO, little gain.

[@saeedkizzy]

hi, what about power(IGN,BAT) and ground check at the module before condemning the HVAC.

[@GkbjlgGkbgljg-my8jc]

You Best 👍😉

[@jamesanderson2176]

A tuned, supercharged, 4-wheel steering PLOW TRUCK?! The customer does snow removal for the local drag strip?

[@rrmech11]

Sweeeeeet Motoyam 👍👍

[@willemstreutgers1154]

Ivan look for software updates and bulletins for this car.

[@notsureigaf]

7:47 be careful with this, I had a pre-07 Suburban that I thought had a parasitic draw but upon testing I found that something in there consistently took 30+ min to sleep, and then it would go from about 120ma draw to under 20.

[@tschuuuls486]

Depending on the cost of those modules, it might be worth it to reflash them with the latest firmware version. Especially if it happens since the vehicle was new :D

[@zx8401ztv]

That traler brake unit must be tied to the wrong side of the ignition switch or the wrong feed fuse.

[@2006Mercury]

SHES LOADED!!!

[@mohawkmike142]

40 millys on the HVAC? not the problem.. Part 2 coming?

[@terrydoberstein6742]

Could one of the vents not going to the proper location cause this also not to go to sleep?