1995 - 2002 OBS GM Truck Fan Speed Switch & AC Heater Control Assy Replacement (Chevrolet & GMC)

[@michaelkeller7789]

My AC switch and the blend doors stopped working one week after replacing the ac compressor. Fan could still blow air out the bottom onto the floor only. AC would not engage the new compressor and the light would not come on on the AC switch. Subsequently, the shop tried two used control heads which were supposed to be functional. Neither worked, then they purchased a new one which operated about 15 minutes and then blew out, allegedly with an odor. Have you any idea what may be causing the control head, the original and the new one, to fail electrically?? 1998 Chevy Suburban K1500, 5.7 liter I need a better diagnostic procedure.

[@DrShock]

@Michael Keller Yeah, this other video should help kzbin.info/www/bejne/gIWzooCigMRjmJY , you have a short in the harness blowing out the power transistor. Bottom of that videos description text.

[@robertvertel9301]

This really helped. Thanks! As a follow up, 19 degrees with snow falling! Got my switch from Amazon for 10.00 and followed your instructions and got it done in less than 30 minutes! I NOW HAVE HEAT! YEAH! Thanks again!

[@s.minicucci2967]

Thank you. What I liked most about your instructions compared to others is that you did not disconnect the wire harnesses where they connect at the panel. You only pulled the panel away from the dash enough to remove the control box. Genius!

[@GWAsnipr7]

Thank you, Big Help! Straightforward, and no BS... I Appreciate You...

[@suns1120]

Had a stereo modification and when vehicle returned ac was not working. I bought the ac delco replacement unit and followed this video to the T. AC now working fine and this video was a perfect guide.

[@robertmoreno9876]

This happened to me so is it just the control I have to replace now

[@troyb.4101]

Very good video, thanks for the work. Changing the whole assemble is the best way to do this job. 1997 truck in Aridzona plastic parts always fail.

[@davidjames640]

This video is fantastic! I have a 1997 Suburban and I bought a new module from Amazon for $70 (Free shipping w/o Prime) and it took me ten minutes to replace it. I have a good mechanic, who I trust, but he wanted $500 to replace the module. I assume he would have spent about $250 of that $500 on a factory AC Delco unit but the cheep module works well. Thank you very much for this video!

[@milesaway3699]

Great video! All I can add is don’t do this in cold weather or in a cold cab if you can avoid it. You’ll break a lot of clips.

[@michaelm2945]

Good vid, I've been putting this off for a while now on my 96 K1500.. The fan switch only knows on and high.. will be glad to get this replaced. thanks

[@VikingNorway-pb5tm829]

Thanks, my part is on the way from USA. :) 10 days delivery.

[@MrRoy-rb1je]

Absolutely exceptional!

[@jimmycorbett4611]

I tried my hardest not to get any of the old AC control to break and was extremely gentle and them damn old plastic clips still broke. Good thing I bought a new unit but still, would have preferred it not to break.

[@Pdubya69GS]

Thank you! Did this today & this video was very helpful. 🤝

[@circa366]

Thanks ! You just saved me 200$+

[@apeacefulgrower]

Very helpful video, thanks for sharing 👍

[@MultiHairypotter]

Excellent, thank u for the help

[@johnhays2514]

exactly what I needed. Thanks

[@DegeneratePerformance]

Very informative, thank you!

[@01keyboard]

Thank you very very much.

[@1okanaganguy]

thanks, buddy...

[@cesars9462]

Thanks man very helpful👍🏻

[@esanzi41]

thank you

[@richk320]

Thanks,my next project on 99 Tahoe

[@richyvillegas3512]

I just serviced my ac after 10years with no ac working on my truck. My problem is when i turn it to max ac it only blows air from the floor

[@emmanueldavis2010]

Thanks,😇

[@davegibson3763]

I replaced this module and I couldn't get flow from the face vents, so I replaced the blend door actuator under the drivers side and the one in the center still won't blow from the face vent, all that is left is the actuator that's by the blower motor but have a feeling that doesn't control that top face vents!

[@DrShock]

The other actuator just controls the flow of heat, from across the heater core, vs cold from the A/C. You may either have a jammed mode door (i.e., actuator cannot move it anymore) or damage in the wiring harness to the control module.

[@davegibson3763]

@@DrShock It may as well be a short that new blend actuator I installed under the dash ,when i move the climate control settings , i dont see it moving,the one under the drivers side does,and the one that controls the hot/cold door does too!

[@davegibson3763]

@@DrShock Is it possible the relay box up top above the glove compartment is bad?

[@DrShock]

I believe you are referring to the resistor pack given the location you are mentioning? If so, that part is only related to the blower motor speeds.

[@davegibson3763]

@@DrShock yeah the blower motor speeds all work just fine,im tempted to just buy another climate control module and see if that solves it,thanks for the reply and the choice videos too!

[@barbiesawada5916]

I have a 1995 S10 and the climate control module is needing new bulbs. Mine twist lock into the back of the unit. Having issues getting the bulbs out. Are they soldered or just really tight ?? And would you know bulb size , would like to put blue bulbs or LED back in.

[@DrShock]

As I recall on these trucks from the 90s that's a one piece twist off lamp assembly onto the flexible printed circuit. They can be really tight after all these decades, just be sure you're trying to loosen and not tighten. The soldered in ones don't have the grey plastic twist lock piece on the back, but rather just the two leads soldered directly onto the flexible printed circuit itself. I don't recall the size, it was a GM proprietary part, but it should be similar to this other video I have here - kzbin.info/www/bejne/rnPKc3asesqNpLs

[@barbiesawada5916]

@@DrShock yes , had to take a pair of needle nose pliers and gently pull it out. They are actually a rare bulb hard to find , a T1 3/4 wedge base.

[@howitzerdriver7687]

Different switch on 1995 (Model change year)

[@MatthewVanArsdale]

I have all (full fan) or nothing, nothing works when I change between the other fan level settings. Is this the switch or is there a fuse somewhere?

[@DrShock]

It's either the fan switch, or the resistor that controls the fan speeds the swith has selected. Search here on YT, there should be some other videos to help narrow it down.

[@stevecarlson6462]

I have a 1998 chevy pickup and everything is working fine except I'm hearing a random clicking sound from the hvac control unit. It used to be fairly infrequent but it's all the time now. Anyone have knowledge of this?

[@deibysalamando9659]

Thank you for your video. Question : how can I change the wires? . I turn my ac/heat on and doesn’t work until I hit the bottom right by the passenger side

[@DrShock]

Are you describing a short or loose connection in the wiring harness by indicating you have to physically "hit" the interior trim area to get the circuit working?

[@deibysalamando9659]

Yes

[@deibysalamando9659]

DrShock how can I fix this ?

[@DrShock]

If both AC and heat are affected, that does sound like a wiring harness issue. I would pull the control assembly out as shown in the video, and inspect the flat style harness coming into the passenger side of the control assembly. If the connector is OK (retainer not broken off making it loose) I'd trace that harness thru the dash area to find the short.

[@dennisalbright6313]

Good video and camera work... I am now leaving my fan switch on the second setting all the time after it became "intermittent" but would like to replace just the switch..... but the broken tabs concern me.... my plan is to wait a bit and then heat those two white little tabs first before trying to use a screwdriver to pry them to release the switch, thinking the heat may soften them a bit and make them more pliable..... If that doesn't work, can I possibly use a couple drops of super glue or JB weld to hold that switch part to the front panel part? Why? The cost of a switch is $10 from China and wait two months, or $11 from Califormia (Ebay of course)..... I think Rock Auto was $25 plus shipping for the entire unit as you showed near the end.... and then the great American rip off because several others parts outfits were asking $100 for it and one even was asking $400 for the unit.... Anyway, let me know if I can glue a switch in, and then fasten the tab with the screw you initially took out... and if that would work.... thanks....

[@DrShock]

When you ask about gluing the "switch" I think you're really asking about the control unit assembly here (the complete unit with the three knobs). The fan switch itself is held in by a bolt as I show, so there's no problem securing that. But yes the type of plastic GM originally specified here, degrades very quickly over time becoming brittle and prone to breakage. If you try the heating approach, be careful not to melt the surrounding dash. That dash plastic may have a lower melting point than the control unit material. You might try velcro strips or something more tolerant of the road vibrations this part will have ot endure than a chemical adhesive.

[@dennisalbright6313]

@@DrShock For whatever reason, the fan switch started working again which I suspect to be a contact issue.... and will wait and see.... If the worst happens, I have a plug in external fan/heater/defroster unit I can use until I can buy the right part.... And as you might suspect, the prices for this part are all over the place from cheap to outrageous and everything in between.... The only other problem similar is a "rattle" that comes from the radio plastic mounts and wonder if one is broken... I might try the velcro idea there too... replacing the radio is easy according to the video... IF you have a tilting steering wheel... Mine is a W/T so I don't..... The radio also has that typical problem where it drains your battery unless you remove one of the two fuses that controls the radio memory.... pain to reset it each day, but......

[@gregory9808]

So i just bought a ‘95 K2500. That gray connector on the very R/H side doesn’t exist in my truck. Is that supposed to be like that or is it possible it was re-wired?

[@DrShock]

1995 was the first year for this interior design. It looks the same on the knob side as the later model years, but uses a different AC control circuit board (part numbers in the video description). They are the same wiring harness but the connector end is a square shape instead of flat like 1996+.

[@MrOiram46]

Do you need to disconnect the battery before doing this or no?

[@DrShock]

If you don't use any metal tools around the module, no you can safely leave it connected. If you find yourself needing to use any metal tools to disconnect anything though, safer to disconnect the negative battery terminal to avoid any shorts.

[@MrOiram46]

@@DrShock Ah, thanks for the info!

[@alvendetti4600]

95 is seperate from 96

[@christenbodtker3326]

Ok I’m reaching out for help here. My ac was only working on high but I had to jimmy the fan switch to get it to work so I replaced the entire AC module. Unfortunately the AC is not working up front at all. Any advice? Also thank you for your easy to understand video.

[@DrShock]

Only working on "high" sounds like it was just the blower motor switch, presuming you meant high on the fan setting. For a new control unit to now not work at all, I would start with the basics. Reinstall the original and confirm the same behavior you had before is there. If yes, the new unit _may_ be defective. If what you meant was AC works, but you're not getting output from some vents that could be a blend door actuator problem.

[@christenbodtker3326]

DrShock thank you!

[@blakemeyer2]

Thanks for the video, I had the whole cluster replaced around 3 years ago because nothing was working, heat ac etc. Just recently I was only getting air on full blast, now it will only sometimes go on full blast. I replaced the resistor and i am still having the same problem. Could it be the switch has gone bad already or any other ideas? Thanks again

[@DrShock]

Fan speed only working on high is typically the resistor pack array on top of the blower motor enclosure. The high speed fan switch setting bypasses the resistor pack altogether, which is why when only that works it typically means the resistor pack is at fault. But it can be the switch as well, though less often. But since you say you already replaced the resistor pack, I would tend to want to get out the multi-meter and test the old resistor pack before going after the switch. No need to pull the one you just installed out again, if the previous pack is good you know it was the switch all along. If you can fit in there, you can even use the meter to check the output from the switch at the resistor connector and validate the switch as well. Pin A (LO input), Pin C (Medium 1 input), and Pin D (Medium 2 input). Pin B is an output to the relay. You should read voltage at each, depending on the fan speed selection.

[@samanthamascarenas0023]

How do you know if the climate control switch is broken.? On my truck I'm able to turn it on then within the min it'll turn off.

[@DrShock]

Which switch are you specifically referring to, the rotary fan switch or the A/C bush button switch? If the latter, with the orange led indicator, it shutting off after being turned on indicates a compressor shut off condition usually (e.g., low refrigerant pressure, high refrigerant pressure, etc).

[@MsWesly1122]

After replacing the bad components on the ac and heating control has anything gone wrong since then over time?

[@DrShock]

Nope, typically the only thing I've found that could be recurring is when you have a short it can blow the control assembly power transistor until you fix it - kzbin.info/www/bejne/gIWzooCigMRjmJY&lc=UgygIH3B8QbsvWduoVl4AaABAg

[@stevenarehart7139]

Where did you purchase your new parts.?

[@DrShock]

If the GM part is still produced I try to use rockauto.com (with a 5% discount code), if the part is discontinued I always use eBay

[@grenadecraig9619]

My switches work just fine, but the bulbs are out. What kind of bulbs are they? I've tried searching online, but I can't tell for sure if what I'm seeing are the ones I need or not. Could you or someone here show me a part number or a bulb type number? Thanks! I'd appreciate it

[@DrShock]

I believe these HVAC control module illumination lamps will be a 74 size bulb.

[@FromthaRoots4]

What if the fan switch is fine but the wire harness is bad do you know the part number for it

[@DrShock]

With the age of these trucks, finding a new harness might be unobtainium. For that I'd suggest going to a pull your own part salvage yard like your local LKQ.

[@taddavidson1407]

I have 1995 chevy 1500 diesel .My A C and heat just stop blowing completly and after a few seconds or so , it will come back on

[@DrShock]

If its both AC and heat, and randomly shuts off and comes back on again, it could be several things. An intermittent problem in the wiring harness between the fan switch and the blower motor, intermittent connectivity within the switch, or intermittent connectivity within the motor (or some combination). To track it down I would do some disassembly at both ends and inspect the wiring harness and connectors first. Then the switch, then the motor.

[@naesean16]

How do I know if I need a new actuator or just a new switch? My fan only blows on feet

[@DrShock]

That symptom isn't going to be the fan switch. It might be the motor that controls the zones, but it can also be a failed control module - kzbin.info/www/bejne/gIWzooCigMRjmJY

[@jacobgreen1947]

I turned my ac on Yesterday and now it want go off. The switch is on off but he just keep blowing any suggestions about what the problem could be?

[@jacobgreen1947]

I have a 98 GMC Sierra c1500

[@DrShock]

Presuming you're talking about the blower fan, and not the AC cooling itself (as that could be many things from stuck AC clutch to bad AC relay), I would start with testing the blower motor fan speed switch. They can get where the "off" position is damaged internally. If the problem is not all of the speed positions work for the fan, this is more likely the blower motor resistor assembly.

[@jacobgreen1947]

Thanks I'm check it out tomorrow n I'll let you know how it goes

[@jacobgreen1947]

So I go to the junkyard to buy a use ac panel n It's work but no ac now n the air only blow on defrost. After observing the old ac panel I noticed the ac blower switch was bad so I'm just order a new one in put mines back in and hopefully the problem will be solved. Thanks again for the help

[@hunterwilson1508]

Where can I get a brand new one of those AC switching

[@DrShock]

Links in the video description for both the fan switch and a complete assembly from ACDelco.

[@noramurphy9070]

Hey brother I truly need to understand how you figured out it was the fan control switch ...I truly thought resister no then I thought fan no then because my locks stopped working thought the ground wire replaced got more power but damn im really gonna use a wood stove if the controller switch is not it...funny thing is build you the engine in 5 hours 🤣 but wiring has me like why lol 😆 why do it like this 😂 engine more easy than the wiring 😆 🤣 😂

[@DrShock]

There's a few fan blower parts involved; the switch, the resistor pack, the relay, and the fuse. Its usually the switch or the resistor as the fuse is an all dead situation. And you can check the resistor with an ohm meter to be sure, but typically when only high works its the resistor (but not always so you have to test). When only high doesn't work I'd suspect the relay. When it's a problem where it won't shut off, or low doesn't work I'd start with the switch. But still not throwing a part at it, just start there with a meter and confirm it's really the switch before buying a replacement. Hope that helps.

[@noramurphy9070]

@@DrShock your RIGHT amazing how fast you replied this guy is on point with he's electronic game I will learn just tried to avoid it have others do it now its kicking me in the butt thanks again for explaining it help me 100percent good starting point 👍

[@hunterwilson1508]

Where can I get the switches in the board and everything need it for my 95 Chevy

[@DrShock]

I believe I only have the part numbers for the 1996 and higher in the description since the 1995 and earlier is a different design and little bit different procedure to remove than the video shows since the dash is different. But the search links might pull up some 1995 ones, check it out.

[@hunterwilson1508]

@@DrShock I thought 95 and up dashes were the same

[@DrShock]

I did too but a few folks commented otherwise so I changed the vid description. If you can confirm I'd appreciate it. I've done a 96, 98, and 99 so I know those are the same. But I've not done a 95. I did check the part numbers for 1995 and will add those to the description. It's ACDelco 15-72267 for no rear defogger and ACDelco 15-72266 for with.

[@philliptorres5944]

97 chevy s10 only blows cold air when driving. any advice what it could be?

[@DrShock]

If the fan speeds are OK, and the AC system is working OK, then I'd suspect the blend motor that controls routing the hot/cold air. There are two of these flat looking motors, one controls the zone (floor/front/defroster ducts) and the other the conditioned/heated air blending.

[@philliptorres5944]

@@DrShock thanks for your response brother. its actually the plug that connects to the blower motor.

[@philliptorres5944]

@@DrShock all i do is wiggle the plug to the blower motor and it turns on its a knew blower motor.

[@DrShock]

Ah I took your comment to mean a temperature problem - _only blows cold air_ - there. Sounds like you mean the fan/blower only works at all - while you're driving. Well if you're seeing it work when moving the wiring harness by hand, that to me points to a break in either the harness, plug, or blower motor connector. If it's a new blower motor (presuming this behavior only started after it was replaced), I'd start with unplugging that and seeing if there's a problem with the connector. You want to be sure the connector on the harness securely locks onto the motor plug to keep a good connection. And you want to be sure the pins on the plug are not defective, and correctly connecting into the harness connector.

[@philliptorres5944]

@@DrShock yeah something with that connector is going on. im going follow them wires and loom for breaks in the line but if it ever turns off i just need to play with that plug. Could that plug be bad like burned on the inside of the connector?

[@DavidSmith-cp7ro]

Where is the blower control module on these old chevys please

[@DrShock]

The blower is controlled by the switch shown in this video, plus a resistor pack mounted behind the glove box on top of the heater box. There is no module on these years.

[@DavidSmith-cp7ro]

DrShock I’ve replaced the resister and the fan switch, must be the blower motor

[@DrShock]

You didn't mention the symptoms you had, if it was fan stuck on only one speed it's going to almost always be the switch. Works on all but one speed, might be the switch but then also could be the resistor pack. Doesn't work at all, you check the switch, resistor pack, and wiring harness to be sure - but its usually going to be the blower motor. It makes noise like the blower motor fan blades are churning leaves or debris - well they very might well be so you check that first, but it's usually the bearing for the fan blade assembly and again you have to replace the blower motor assembly for that one too. Hope this helps.

[@DavidSmith-cp7ro]

DrShock it was my blower motor, there were no symptoms, it just wouldn’t run at all.

[@MarioMartinez-yo5ns]

Podrá usted traducir los vídeos al español. ...si fuera posible estaría muy bien. .grcacias

[@DrShock]

Gracias, estoy por investigar esto. He traducido uno de mis otros videos al español para ver cómo va.

[@MrBowNaxe]

Been there, done that... My problem is the fan cuts of intermittently even after installing the new assembly. First time I thought it was doing that because I went cheap and didn't get the ACDelco one but a couple of years later when it started doing it again I thought "That's what you get when you get the cheap Chinese version." I replaced that one with the part you listed and it worked great for about a month. Now when I hit random bumps it cuts out. Is this going to be a harness issue I'll have to chase down? Anyone ever have that issue? Thanks for posting!

[@DrShock]

It cuts out completely and forever, or just cuts out intermittently?

[@MrBowNaxe]

@@DrShock intermittently

[@DrShock]

I'd suspect a bad ground then, or inspect the fan switch. If the switch is getting overheated, melting the plastic, I'd check the blow motor resistor pack.

[@MrBowNaxe]

@@DrShock Finally "cured" my issue! I replaced the eight pin (6 actual wires) wire connector. I found one power wire that was loose and couldn't fix so I replaced with $3 salvage yard part!​

[@boricuaenutah350]

What's the name of that tool? Please

[@DrShock]

Are you referring to the yellow trim removal tools?

[@alexis_1503]

does any one when the ac harness leads to the back , where it might to connected ?

[@DrShock]

Alot of wiring in those harness connectors going to a variety of places from the control assembly, was there something specific circuit wise you're looking for?

[@alexis_1503]

just the wire harness that is attached to the hvac , the single connector on the other end of the harness

[@DrShock]

If the large flat connector towards the passenger side, that is the main circuit. You'll have the light green wire heading into the engine bay to feed the pressure sensors and ultimately the PCM. Other circuits from there are the two blend door actuators for temperature and zone direction in the interior. You'll really need access to a factory service manual to make sense of it. The connectors on the drivers side are the rear defogger circuit, if applicable, and the fan speed selection switch harness.

[@blairjosephbernard2011]

Don’t need those tools.