They Replaced The Alternator On This Ram But It’s Still Messed Up! (Part 3 Why You Need A Scope!)

This one has an interesting backstory and really shows the reason we love scopes. This one came to us after going to another shop, but still having problems. We don’t think they necessarily diagnosed anything, but they said the issue was a bit over their head and sent him our way. At least they didn’t get into something they weren’t comfortable with! That’s highly commendable.
But if they had a scope and the knowledge on how to use it, then it never would have needed to bounce from shop to shop. This video will show you why. Hope it helps. Enjoy!
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[@johnrpizzaguy]

Replacing both the battery and the alternator is a huge red flag to begin with. As a 40 year master mechanic I “Test not Guess “. Great video Sherwood

[@kc360awareness]

First off- I’m not an argumentative commenter. I would like to offer a counterpoint…. I have maintained a fleet of 20-30 vehicles for over 25 years. About 15 yrs back started replacing batteries preventatively between 3-4 years of use. There has been a remarkable decline in the number of starters & alternators being replaced. With that in mind is it really a red flag to replace a battery along with a failed alternator? Obviously there are lazy/sloppy/greedy service providers that simply want the upsell, but I don’t see it as a red flag when a thorough repair is the goal. Again I’m not intending to argue the point.

[@jeffhesse8415]

​@kc360awareness I've been an auto mechanic since the mid 80's and now a shop owner/ mechanic. I've seen a lot of batteries go bad and cause the alternator to overwork and go bad. I've also seen alternators go bad (over charging) and cause the battery to go bad. So I agree with you, not necessarily a red flag. Excellent observation on swapping batteries for preventative maintenance and prolonging alternator and starter life. My practice is to test the battery on every car that comes in and recommend replacing if they are starting to show weakness.

[@nu3qamateurradio930]

Yep - test don’t guess.

[@Hellcat71782]

I mean it’s kinda common to see someone refusing to replace their alternator until it dies and at that point they smoked the battery. I mean people don’t even change their oil and that’s cheap to do.

[@robertjones6971]

You should now be the " bater " mechanic.😜😜😜😜

[@Un_brainwashed]

There's a huge difference between a mechanic and a TECHNICIAN.

[@paulsolovyovsky1702]

root cause analysis is the opposite of a parts cannon. Great tutorial

[@pontiacsrule8761]

Great video as always. He gets right to the point with excellent camera work. That aside, he is so professional. Never bad mouths another shop. That's a true, honest mechanic & person right there. He makes everything look so easy. It's because he really knows what he is doing.

[@greggc8088]

Module rebuilders are getting real good at replacing those drivers and it saves programming. PPT for the DTC you had shows using a real test light while commanding field control from lo to hi percentage and watching the change. More than one way to milk a goat though. Thanks for sharing. Side note-I keep my Pico in a dedicated cart and ready to go so it really doesn't take too long to set up when using.

[@simplygregsterev]

@@greggc8088 only issue is turn around time. A place near me is 7-10 days for a repair. New ECU can be had within a 24-48hrs or even used (yes you can reprogram) Nice job on dedicated cart. Its something im assembling

[@petesky007]

Impressed you guys have the ability to change modules. We had a BMW 3-series (E90) and over the period of 2-3 years we had 3 modules go. These modules were BMW only supplied and they need coded to the car once fitted, again this was something only the BMW dealer could do. Once fixed, we ditched BMW and have never been back.

[@eddiereichel9354]

Im a 1 man auto shop in a small town in NWPA. I own a 09 328i I myself can program and code not only BMW but just about any make and model.

[@petesky007]

@@eddiereichel9354 That's very impressive, I take my hat off to you sir! The module(s) that went in our car had to be ordered on the basis of what was fitted to the car e.g. if xenon lights were fitted then a different footwell module part number had to be used. No other repair shop at that time could code the module to the car other than BMW and I'm not sure that even now anyone else near me could.

[@sheerwillsurvival2064]

I don’t have a nice scope so my method is to use bidirectional scan tool and test light . Command PCM to charge and see if test light flashes. Poor man’s test 😉 great video as always

[@ThunderbirdRocket]

Nice work around ! 💡

[@TracyCorbett]

Here's my scope test request: I would love! to see a relative compression test adapted to a hybrid vehicle that uses the electric drive motor to start the combustion engine, such as Priuses do. Toyotas have a relative cylinder speed test (which stands in for the usual cranking relative compression test) available via scan tool, but I would love to see that measured via amp draw - by setting up a cylinder 1 trigger along with recording the amp draw of the high voltage drive motor when cranking the engine. Love what you guys do! Thanks for all the awesome content

[@ThunderbirdRocket]

Good one 👍🏼. That would be useful .

[@PaulOneel]

Keep postings these regardless off difficulty of diag. Scope work is awesome. Thanks. Btw can you give us an uodate on Joe Auto Electric? I havent seen a post in 3 yrs from him

[@HuntsWorkshop]

Excellent video! I am sure that Sherwood checked for this outside the video, but for a DIYer, there is 1 more potential issue besides bad pcm. The brn/gry wire may be shorted to ground somewhere since this is a backprobe test with that wire still connected. That leaves a possibility of pulling the ecm pin 19 to ground. A simple test light will check for that.

[@jonathanfournier4084]

Thanx sherwood for your 12v direct testing at alternator terminal. Will be using

[@ThunderbirdRocket]

Excellent videography (professional quality) . Tremendous coaching (simple but accurate trade terminology ) I appreciate your building in review - reinforcement comments . The pace is perfect to literally memorize the concepts being discussed . Have yourself a fantastic weekend with family and friends and pets !

[@trekOCLVone]

You are getting close to 100,000 subscribers - Your efforts are appreciated, and your channel is set to grow .

[@sheerwillsurvival2064]

Good stuff keep them coming and numbers will grow

[@anthonysova7117]

Good video thanks Sherwood

[@shaunblakemore7150]

Great job 👍

[@crasher88]

I'd love to see more GDI injector and high pressure fuel pump solenoid scope waveforms control and brake down of each part of the waveform and some examples of bad(If you can get them)

[@jimstocks]

Bought my first scope in 1972 only did analysis on ignition systems worked my way up in 1984 to a Sun scope that did most tech from the times I now have a portable unit that covers most stuff & I’ve never looked back. To see it is to believe it 😊

[@Popotla]

Fabuloso!

[@vickenkaragozian2041]

You can use the Escope 5v pulses from the ecm to the alternator on the field wires to see if the alternator is doing its job. Love the Escope. Best thing i ever did to but the Escope. Thank you for posting videos with Escope. My favorite diagnostic tool.

[@matthewzoelle9149]

Seen as how you asked, I like hooking a scope up to abs wheel speed sensors to test them. Really I just like spinning the wheel while I watch the scope, mostly because I have the maturity of a 10 year old.

[@michaelmiller7601]

Hey Sherwood nice job

[@martylandry751]

Good Job

[@user-bn3gy5wl2r]

Haven’t watched the video yet but I’m sure you mention this. Always check generator pulse width on the Chryslers because the regulator is internal to the pcm. I put a lot of those in at the dealer. Edit: after watching. On the dealer scanner I believe the number scale it shows goes up to 999 not just 100% and that was always the dead giveaway the ecm was bad. It’s nice to see it shown on a scope and not just a because the book says this is it kinda explanation.

[@jwoeltje6949]

Great job! Not that you ask for my input but I probably wouldn’t back probe. Maybe not in this case but if I had pin contact issues u could miss it seeing u helped make better contact

[@deerhunter8533]

This is a very common problem with those Motorola NGC5 PCM’s. The driver that controls the alternator field fails. I have repaired hundreds of them

[@zackclark2214]

Would love to see how you guys deal with aftermarket warranties customers have. My experiences have been that they are like health care insurance companies dictating how you do your job.

[@user-ve8mx3zi6k]

Another good scope video! Can you do one on basic setup so techs can get usable info on the screen quickly. It was a struggle for me initially to search around and find all the options . I realize there's quite a few different scopes out there with different steps to use. FWIW, mine's an Autel 4 channel and has served me well. Thanks for the video. Al H.

[@humblebeginings777]

Love this....

[@DependableAutoTruck]

on the older dodges to help customers many of the alternator shops install external regulator to keep from replacing computer is that a option in your shop

[@martinarrieta248]

Grasias

[@juanfgonzalez2039]

👍👍

[@provolone1876]

Way to go what a Diag

[@GripFreak]

Curious as to why you test the voltage drop on the positive side of the charging system but you didn't mention checking VD on the ground side? I've seen this bite many techs for failing to check VD on ground side of circuit. The biggest mistake in electrical diagnostics is assuming you have a good ground just because you have B+ to the component. This has been my experience. Great to see you encouraging the use of a scope. The main reason techs avoid scopes is because they don’t know how to use one and not having a solid understanding of DC electrical fundamentals. Your series should help many techs.

[@daltondavis0668]

Sherwood is meant for the camera! Gets better with every video.

[@mayowaodus6310]

Great diagnosis

[@TekkHakk]

Sometimes the diodes in the alternator can leak, cause a short, and drain the battery. You can use a meter to test.

[@t.k5928]

Hey Royalty Auto nice diag video. One thing I didn’t hear you mention is about terminal fretting or pin drag test at ecm and terminal connector on field control wire. Or did i misunderstand your diag process? Thanks

[@jass9091]

Can do video on how to diagnose bad ecm

[@luigirubino1487]

Great stuff! How do we enroll for the contest giveaway?

[@DD-gd3fr]

My Dodge truck same thing had to replace the Ecm. Thats a expensive voltage regulator. Miss even external Regulator. Its Crazy. Sherwood , If the ECM was good and you probed it with your power probe would it destroy the ECM?. Thank you for your work.. I've never had much scope experience. During my time I have a old Snap On Advantage I be leave it has a scope will it work for these applications? Thank again,,,Don

[@djosbun]

How about scoping a three phase fuel pump?

[@JOMaMa..]

You guys give free consultations?

[@JustHelpMeOuT5466]

Please explain how you find that pin on the connector of the engine control module to probe to.

[@reeldeelz2940]

hmm for DIYers.. scopes geared for automotive diagnosing (4 channel +) I've seen are prohibitively expensive ($1k+)..

[@theroyaltyautoservice]

Stay tuned! We will be covering scopes that are for beginners or DIYers some time soon!

[@simplygregsterev]

HanTek is an option for DIY. That SnapOn scope is around 15-20k last I checked but its really freaking awesome. I use a PicoScope

[@manuelgil6728]

What about the topdon scope with scanner any good?

[@simplygregsterev]

@@manuelgil6728 id go Autel for that

[@smc9764]

@@manuelgil6728 I have the ThinkTool Pros with the scope and they are essentially the same tool just different color. TopDon has some extra features from what I saw, I haven't needed to use the scope yet. But, it looks similar software wise to what they throw on the uScope, which is Android based I believe. I kind of wished I didn't buy it, but there is a DiY TopDon put out on KZbin showing how to use it kzbin.info/www/bejne/h6bapoinrKaEd7c. The ThinkTool scantool is awesome though and I love it.

[@smc9764]

How about the pins and the connectors themselves? I almost threw a throttle body on one of my cars. I was seeing a bias voltage on my scantool and voltage on the wires backprobing and piercing. However, I found out on accident when I pressed the connector really hard the scantool responded, lol. I front probed at the connector, I found Nissan has a little hole under the connector that a t-pin can fit in. There was zero voltage there, so I spliced a new connector and it was fixed.

[@wilstw]

whats a good scope for a DIY person

[@Thomas-fn3yh]

If the field control wire was shorted to ground would it read the same?

[@RATCHETMAN1001]

yes i made some comments on that as well, glad someone is paying attention. I think hes good but not a teacher at this point. i no hes trying very hard but the ones of us who uses these tools on a regular basis and test sees his short comings. let me be clear im not perfect either. but when some one proves to me my mistakes i try very hard to correct them, i dont get angry .so my comments are not for that purpose to down him . i hope he reads these comments if they have merit maybe he will address them accordingly

[@garysgarage3669]

Bad alternator, everyone’s go to.

[@calebmohler3082]

Keep beating this scope stuff till its dead and then beat it till it comes back to life Sherwood lol. Im 33 and mobile to repair shops in the greater Houston area. I use a scope daily if not multiple times a day. I love what you said in the first video, something to the effect of " i dont know how to or I dont know people fix cars without a scope". I tell people almost the same thing all the time. " Im not smart enough to fix cars without a scope". Not meant to be cocky or arrogant. A scope is simply the easiest in my opinion. And then the argument that scopes cost to much is dead. Techs have no problem making weekly payments till they die on hand tools off the tool truck. Some of those special tools they buy they only use once every 5 years. It costs more in my opinion to not have a scope. I don't use it for every car. But when I need it ive got 4 of them on the van lol. Keep it up guys!!

[@cheapers1952]

I know for sure if it is a customer that came to me I would tell them take it back to that shop in demand your money back no ifs ands or buts they tried bluffing their way through by selling them an alternator and a battery and it did not solve the problem so they didn't know what else to do so they said what they said about a draw again your money back ⁉️

[@jedi-mic]

Hi can I pick your brains for a minute! I'm curious is there any special coolant I should use for Mercedes engine petrol 4 cylinder cast iron block I think and the aluminium head M111 it's got a blue one in there at the moment I wonder if it makes much difference they say to use an organic compound I'm not sure what that is under code what's antifreeze or coolant do you recommend?

[@kenputt1750]

Takes me twice as long as I only have 2 channels.

[@MultiChilanguito]

i want to lear how to use the scope its any video on how to set up the scope or any for beginers

[@ablackformula]

I'm curious how you charge for this. This is what it seems like, please correct me if I'm wrong.. The customer gets in the door and immediately agrees to one hour. That hour gets you to the pcm being at fault. You then notify the customer where you're at, and get another hour to test the pcm power/grounds and confirm the pcm needs replacement? This hour to test the pcm may go up if the module is difficult to get to, I get that. And then once the pcm is condemned, I suppose service info will tell you how much more labor will be involved to replace and reprogram the new one? I often watch these videos and imagine the conversations I'd be having with the customer in your place. Respect for you not talking trash about the other shop (you talk about this often.) The fact that they misdiagnosed the parasitic drain and couldn't diag the pcm after the alternator was first replaced kind of makes their first call suspicious, even though there's a chance they were correct. I suppose one thing I would've done different, when applying field to the alternator to prove it worked, I would've applied voltage to the command wire at the pcm. This would ensure that command wire isn't grounded between the pcm and alternator.

[@hughkoontz2166]

Snap on Zeus $$$$$$$

[@cheapers1952]

These fly by night shops need to definitely be held accountable for the concept of just throwing parts at it

[@nowayout73]

Hopefully the customer was smart enough to retain his old parts like everyone has been telling the general public to do for a hundred years so he can put back the OE parts and return the JUNK aftermarket parts that won’t last, get a FULL REFUND from the last shop and if not dispute the charges with his credit card company 100% and/or sue them retaining this video and all receipts as EVIDENCE of a negligence scam! Disgusting and this crap makes my blood BOIL!!!!

[@timmorgan2533]

I don't know how this operates but does the alternator sense wire send voltage to the pcm so the computer knows the alternator output? If so why wouldn't you be worried about that input to the pcm and just at the alternator? Seems like you could have good sense at the alternator but may not be getting to the pcm because of another circuit issue. Tell me if I'm wrong.

[@robertjones6971]

Wrong ghost rider

[@tomc3216]

I have a charging issue on my 08 Altima, brought it to 4 shops they all say it’s fine. My response is if it’s fine why do my batteries die after 2 years. I checked voltage with a basic lighter outlet voltage reader and I can clearly see as I’m driving the voltage starts good 13.8 then it drops to about 12.5volts. I had to start checking the battery with a voltmeter to avoid getting stuck.

[@smc9764]

I am not a professional by any means, but I believe around 2007/2008 is when Nissan/Infiniti started having the alternator charging being turned on/off by the ECM. If you take a lot of short trips it's possible for the battery to actually never charge. I don't think the ECM tells the alternator to start charging until the car has been on for X amount of time or driven in X amount of miles in one drive cycle. There is a way to by pass the ECU control and make the system function like a normal alternator, but you'd have to look up some wiring diagrams to see which wires to modify.

[@TonyRule]

So... they misdiagnosed it despite the fact their diagnosis could be easily disproven with a multimeter. Name and shame.

[@nickayivor8432]

The bottle of water is very good for your body, Royalty Auto Service Take care, Royalty Auto Service Thank you, 📷 man Love it From start to finish 👍 WHIP SMART, Royalty Auto Service From Nick Ayivor from London England UK 🇬🇧 ⏰️ 19:06PM Good Evening

[@tonymaxwell9460]

I just don't understand how the fusible link keeps the current from the alternator from coming out like it was before at 50 something volts, it's after the alternator.7/8/24

[@jamesspash5561]

Why do we need the computer controlling the alternator. The simple internal voltage regulator worked for 40 years. Load increase on system, voltage decreases, voltage reg increases output. SIMPLE.

[@jorgebolivar]

To protect what the cars wasn’t equipped w 40 yrs ago.

[@FortunateJuice]

So the other shop says we can't fix it, but your SOL on the alternator and battery we already charged you for. Unreal.

[@user-tu2jw6lk5o]

At 8:15 the red trace went down (ground) I get that because it was no longer connected to the alternator. Why did the green and white trace (command) go up? Had to be voltage out of the PCM.

[@RATCHETMAN1001]

if the field control is duty cycle to me their should be a pulse width signal. appears its stuck on ground. and if i understand hes checking this at ecm and alternator. if that wire is shorted to ground you will get those readings and may not be the ecm. he did unplug and full field the alternator which proves its good. i would unplug from alternator and the pcm and check ohms to ground on the field wire to prove its not shorted to ground. thats the weakness in using the scope it takes more than the scope somtimes. this is where a scope or multimeter will lead you down a wrong path if you dont follow threw with understanding the circuit .its the brain power thinking at this point. hes not following threw for truth to be seen. i no hes good not knocking him and dont mean no harm. this is where a good teacher would prove out the system and then the scope would be king. or cut the wire close to the pcm where u can prove the wire is not grounded and look at a wave form and if it stayed on ground then i would test power and grounds at ecm for final proof u need an ecm. just my thoughts

[@RATCHETMAN1001]

again what he s not doing. maybe draw out a signal that the alternator should see from the pcm. would be good for people to see and understand so when they dont see it its a visual for people to help them. and understand if the wire is shorted to ground then the wave form hes showing is truth and what ever the fix is(at this point i cant prove its the pcm) but after the repair what a known good is. its always a before and after is where the truth lies and threw data can be proven

[@RATCHETMAN1001]

its like when i went 2years for automotive. the problem i had was they would bring in a car and we would diagnose it ,but we never got to see the fix after the diag .we never got that conformation which we all need, before and after is a big deal

[@jedi-mic]

why do you need to use a scope for? I just put a multimeter on the battery and maybe rev,it and if it goes up you know it's charging.

[@ThunderbirdRocket]

One benefit / reason for using a scope is that a scope can capture / show an intermittent problem. Along with other channels hooked up to equipment on the car (integral to system operation) the root cause is distinctly identified - and not just a mere symptom of the source problem .

[@epicragegaming2016]

so he can look at many data points at once.

[@jamesspash5561]

Over complicating simple systems.

[@victorgonza4528]

If you can get rid of the “hmmm” from your speech, the information would flow much better. Great video otherwise

[@31acruz]

Why don't you show people how to do that with a simple Volt Meter? not everyone will go out and spend 5 grand on a professional scope like you did.

[@straydawg13]

Because this channel is geared towards professional technicians. Maybe you should make a video demonstrating how to do it with a voltmeter.