2003 Envoy SLT - Front Air Conditioning Not Blowing 100%

[twolaver]

I have a 2003 GMC Envoy SLT with 65,000 miles. It has front and rear air. The rear air works fine. The front air will blow on high when the cars starts, but within a minute or two it slows to almost no air. I checked the fuses under the hood and they seem to be okay. Is this a blower motor problem or a short in the wiring? Any suggestions to trouble shoot would be appreciated. Thanks!

Thanks for your comments below. The fan/blower wimps out after driving the car for a couple of minutes. I'll shut the AC off for a few minutes and turn it back on and it blows on high again. It's not a cold air thing - even when the front fan stops blowing on high a small trickle of cold does come out and the rear air still works fine. The Fan Switch - any hints on the car where I can find this part. I assume this is something I can replace myself vs. the dealership service dept.? Thanks again..

[BRD]

Do you mean the fan/blower is wimping out or the A/C itself, as in cold at first but then weak? If it's the fan losing traction I'd suspect the fan switch. They usually hold up OK. If the A/C isn't blowing cold I'd suspect either you've lost a little R134a refrigerant or, if it works like it should but seems to be an off and on deal, the high-low switch. It's screwed onto the shrader valve at the accumulator, has a 2 wire clip running to it, easy to replace, runs about $20. GM OEM'd a bunch of defective high-low switches on '02-'04 Trailvoys. They know about them. If you bought your Envoy new there's a decent chance your dealer's service dept would fix it and GM cover the cost. You're due for a $39.95 A/C check-up anyway, see what you can finagle. Good luck.

[BRD]

One more thing just came to me (which you don't want it to be) - If your refrigerant's too low (leaked out) or the compressor is overheating for some other reason - e.g., no oil - the system will shut it down so it doesn't burn up, same as your central HVAC at home.

[envoyxuv]

You may want to inspect the wiring/connections at your blower motor and blower resistor. Do you have manual (passenger and driver have a separate slide adjuster for temperature) or automatic air conditioning? (automatic has the blue light up digital display)

[twolaver]

Originally Posted by envoyxuv

You may want to inspect the wiring/connections at your blower motor and blower resistor. Do you have manual (passenger and driver have a separate slide adjuster for temperature) or automatic air conditioning? (automatic has the blue light up digital display)

I have an automatic air conditioner and recently purchased a blower resistor. Any hints where to look for the blower motor? I'm to take the panel under the glove box off and start there. Thanks.

[envoyxuv]

Originally Posted by twolaver

I have an automatic air conditioner and recently purchased a blower resistor. Any hints where to look for the blower motor? I'm to take the panel under the glove box off and start there. Thanks.

Make sure that you have a blower motor control processor (also called a 'linear power module'), not a resistor. It unfortunately also costs more than a resistor, because GM is proud of it. The automatic heating/air conditioning controls use a different fan control (processor instead of a resistor) than the manual controls. You'll know by looking at the one in your envoy and comparing it to the one you've purchased if you've got the right part or not. The plugs won't match.

You're headed in the right direction to find it. Once the hush panel is removed from the under side of the glove box area, you'll find the blower motor and the blower control processor.