A/c Won't Work...again!

longtalltechsan · July 23, 2009

I have a 2006 Silverado Crewcab. Less than a year ago my a/c stopped working. After reading on here, I replaced the blower resistor and we were back in business. Now, just 10-11 months later and in HOT weather, it stops working again. The a/c does not work on any speed. Last night I pulled the resistor and it looks fine, although on the wiring harness that plugs into the resistor, the E wire (third from left) and about 1/4" back from the connector is fried. So what do I replace?

I went the the chevy dealership this morning. A new wiring harness is $90 and they said you just clip off the wires and connect the new one. Seems to me that the wires may not be big enough and that is why it fried. Or is it the resistor again? I then went to the service dept and they want $105 just to tell me what's wrong. The guy there said he had an '04 and that he had to replace the head unit twice! What the hell is up with that? No wonder GM went under. The ac/heater control unit is $250 although I can find it cheaper elsewhere.

So my question is what do I replace? Do I start with the wiring harness because no matter what that has to be replaced anyway. I would appreciate any help ya'll can give me.

Thanks.

longtalltechsan · July 23, 2009

Could really use some help here. Anyone?

Spurshot · July 23, 2009

Jon,

I'd get a Helms/GM manual for your truck. They have extensive troubleshooting sections in every chapter. A manual will pay for itself quickly.

You might check to see if the blower motor is drawing excess current. Motors can have problems that cause excess current draw. But I'm not sure the blower motor is in the circuit that burned up on your truck without looking at a schematic (also in the Helms/GM manual).

txab · July 23, 2009

You need this wiring harness replacement

longtalltechsan · July 23, 2009

Thanks for the replies. I am going to start with the wiring harness. The resistor still looks good. Is it possible to just have to replace the wiring harness w/o having to replace the resistor?

jrrod2004 · July 23, 2009

My recommendation: Replace the harness as well as the resistor. My HU went out on the HVAC system, causing a replacement to be installed under warranty. Accordingly enough, the resistor was determined to be bad by the dealership just outside of my warranty but they covered at their expense since I had the truck in for regular maintenance anyway....have no clue about the harness..

longtalltechsan · July 23, 2009

I went and got the wiring harness from the dealership. Thanks for the link txab, but it is hot as hell here and I NEED a/c. Anyway, they looked at the resistor and said they thought it looked good. If not, then I'll have to buy that too, but hopefully it is just the wiring.

bigbengalbubba · July 23, 2009

You need this wiring harness replacement

That's a great link! That kit costs less than I paid for just the resistor. I didn't see any burnt wires at the time of replacement so maybe I'll be ok.

Spurshot · July 23, 2009

If the breaker keeps tripping in your house and some wiring frys, wouldn't you want to know why before you replaced the wire and reset the breaker?

tramz · July 23, 2009

About a month ago same thing happened to me. Fried the third from the left and at the same place on the wire. It was highly recommended to replace the pig tail and resistor. I got the resistor from O'Reilly's for around $25 and the harness from the dealer and got a deal on it, under $70. I also went and purchased the kit from Motor City just incase, so far so good.

http://www.gm-trucks.com/forums/index.php?showtopic=98603

pm26 · July 24, 2009

Do you guys recommend replacing the resistor preventively to prevent these problems? I have a 2006 crew cab with low miles (about 10,500) and no problems with A/C yet. However, I am annoyed to find out that this is yet another defective part GM has snuck into these vehicles, knowing full well that it will cause problems down the road.

So far we have these questionable low quality/reliability parts ont he GMT 800 series:

intermediate steering shaft

driveshaft yoke

blower motor resistor and wiring

4WD selector switch

power steering pump (prone to making high pitch whining noise)

cheap front brake rotors/pads

cheap rear brake shoes

cheap stamped steel differential covers that rust

cheap belt tensioners

questionable 4L60 transmission internal parts

Anything else? Please add to the list.

I am wondering if I should just sell the truck or trade it in on a new Dodge Cummins 2500. Unfortunately, it would cost me about $ 18k plus my truck to do this, and Dodge trucks have their own problems as well.

Bowtie2Sierra · July 24, 2009

Do you guys recommend replacing the resistor preventively to prevent these problems? I have a 2006 crew cab with low miles (about 10,500) and no problems with A/C yet. However, I am annoyed to find out that this is yet another defective part GM has snuck into these vehicles, knowing full well that it will cause problems down the road.

So far we have these questionable low quality/reliability parts ont he GMT 800 series:

intermediate steering shaft

driveshaft yoke

blower motor resistor and wiring

4WD selector switch

power steering pump (prone to making high pitch whining noise)

cheap front brake rotors/pads

cheap rear brake shoes

cheap stamped steel differential covers that rust

cheap belt tensioners

questionable 4L60 transmission internal parts

Anything else? Please add to the list.

I am wondering if I should just sell the truck or trade it in on a new Dodge Cummins 2500. Unfortunately, it would cost me about $ 18k plus my truck to do this, and Dodge trucks have their own problems as well.

I suggest selling or trading off that piece of crap asap. GM didn't get anything by you, did they?

Zembonez · July 24, 2009

I went and got the wiring harness from the dealership. Thanks for the link txab, but it is hot as hell here and I NEED a/c. Anyway, they looked at the resistor and said they thought it looked good. If not, then I'll have to buy that too, but hopefully it is just the wiring.

I can understand you being pissed but luckily there aren't too many issues with these trucks. Every vehicle has its weaknesses. If they didn't, there wouldn't be a large service department full of broken ones at every brand's store.

It does suck that these damn trucks aren't perfect!

longtalltechsan · July 24, 2009

I went and got the wiring harness from the dealership. Thanks for the link txab, but it is hot as hell here and I NEED a/c. Anyway, they looked at the resistor and said they thought it looked good. If not, then I'll have to buy that too, but hopefully it is just the wiring.

I can understand you being pissed but luckily there aren't too many issues with these trucks. Every vehicle has its weaknesses. If they didn't, there wouldn't be a large service department full of broken ones at every brand's store.

It does suck that these damn trucks aren't perfect!

I will agree with you that they are great trucks. I can't think of any other problems I have had. The thing that pisses me off is that GM knows about this and they won't do anything about it. I read several stories of people's cabs filling with smoke. If true, that is a huge safety issue that should be addressed by the manufacturer. And if you have a recurring problem with something that as soon as you walk in and tell the parts guys about a/c not working they immediately get up and go get the exact parts you need. That screams of an issue that is faulty engineering. And in that case, it should be a recall.

I installed the new wiring harness tonight and it worked. I am really happy that I didn't have to drop anymore money on this.

Zembonez · July 24, 2009

I went and got the wiring harness from the dealership. Thanks for the link txab, but it is hot as hell here and I NEED a/c. Anyway, they looked at the resistor and said they thought it looked good. If not, then I'll have to buy that too, but hopefully it is just the wiring.

I can understand you being pissed but luckily there aren't too many issues with these trucks. Every vehicle has its weaknesses. If they didn't, there wouldn't be a large service department full of broken ones at every brand's store.

It does suck that these damn trucks aren't perfect!

I will agree with you that they are great trucks. I can't think of any other problems I have had. The thing that pisses me off is that GM knows about this and they won't do anything about it. I read several stories of people's cabs filling with smoke. If true, that is a huge safety issue that should be addressed by the manufacturer. And if you have a recurring problem with something that as soon as you walk in and tell the parts guys about a/c not working they immediately get up and go get the exact parts you need. That screams of an issue that is faulty engineering. And in that case, it should be a recall.

I installed the new wiring harness tonight and it worked. I am really happy that I didn't have to drop anymore money on this.

Glad it's fixed. Many times large companies seem to leave us out in the cold on issues that they should "man up" and take care of. Apparently continued support from their customers is not very high on their priority list. This better continue to improve at GM if they want to grow strength for the recovery.