2004 Trailblazer

[stone52]

Hi. I have a 2004 Trailblazer, and just recently the A/C just stop blowing. I have checked to relays and fuses and all are fine, I even checked the fan motor relay thinking that would help lol. I am at a lost right now and have no clue what else to check. I'm trying to avoid going to the dealer, cause they cost to damn much.. If there is anyone out there that can help me out, that would be greatly appreciated, Thank You..

[Ol'Jim]

Did you try it on all fan speeds? Often you will lose 1 or 2 of the fan speeds, especially # 4 & 5. There is a resistor pack mounted right near the blower motor that has a set of resistors in it which regulate the voltage for each of the fans speeds. These molded packs burn out, I have had to replace 2 of them over the past 4 years on my girlfriend's 04 TB EXT.
The last time it lost all fan speeds - The excessive current actually burned the power connector and part of the wiring harness, so I had to order a kit from AutoZone or O'Reilly which included the connector/pigtail that had to be spliced into the harness. Not really very difficult, I think I only needed 8mm & 10 mm sockets to remove the glove box door, and the blower motor enclosure. Check out Trailvoy.com (it is a site dedicated to Trailblazers & their sisters - GMC Envoy's). Instructions & pictures there to help you with this & lots of other repairs.

[brcidd]

Blower motor resistor if you have manual a/c (no digital temp display or control) or fans speed module if automatic climate control- (has temp display and digital control- along with the "auto" button- manual system - resistor pack is about $34-- climate control system module is about $106- both at Autozone.

[Tech II]

Are we just talking blower speeds here?

As the guys have asked, if a manual system, did you lose one or two speeds and then lost all, or did this happen all at once?

Do you have a manual or auto temp system?

[KM Carnes]

Thought I would add my experience from just this week in case it helps. I have the automatic climate control on a 2007 Trailblazer. My blower started to have a life of its own a few weeks ago. The fan would blow at a low speed though high was needed and indicated on the controls. Manual or auto settings made no difference. Occasionally it would inexplicably blow on high though it was not needed. It might run long after the car was shut off, but pulling fuses had no effect. This occurred whether needing AC or heat. I got from this forum that it was a relay problem, but the dealership sold me a "fan" relay, which I found was for the engine cooling fan. Next visit to the dealership got me to a knowledgeable parts guy that suggested a relay/resistor module pack mounted somewhere near the blower. At this point neither of us was 100% sure it was the culprit and I was not able to find the pack location behind the glovebox. Also, by now, I was hating drives without A/C and lacking time to replace it. So I elected to have the dealer diagnose and replace it just to be sure I had the right part and get it done quick. The relay/resistor module was the part replaced and all works great now. The GM part is #19260762. Dealer only needed a half hr to replace.

[brcidd]

You forgot to tell us what it cost at the Stealership...

[Tech II]

You forgot to tell us what it cost at the Stealership...

Yeah, those other garages would never act like a Stealership....

[KM Carnes]

I suppose I left the price off just to avoid the "stealership" comments. But since you asked...
- The part was $136.53 with tax,
- Diagnosis and install labor was $187.50.
With enough confidence, I could have dropped diagnosis. But there was a slim chance the problem was in the HVAC controller. And I probably could find a genuine GM part online for about $100. Overall, for a little over $300, it was well worth it to avoid the sauna in my car for the next week or two until I could do the job myself.
By the way, at 8 years and 160,000 miles I still have under $1000 in repairs. I certainly can't complain about one visit to the "stealership". They were fast and professional.

[brcidd]

The part is $106 at Autozone- I just did one last month.

Also, -- a heads up- your compressor will soon go into the intermittent mode- not run once system warms up. cool at engine start, but quit turning after the first cycle off- not to run again until it cools off, or you hit a big bump.

The cause is the compressor clutch air gap wears too wide to magnetically pull in once magnetic coil windings warm. The answer is to replace compressor $450+ or to remove an air gap shim in behind the clutch plate to put the air gap back at .020". I've done dozens of nippondenso compressors (on Trailblazers, envoys, and pick-up trucks . Average mileage is near 180k+.

The stealerships will not fix like this, they want to replace the compressor- to make the money. if you do it yourself, it cost $0...