Please Help Fix What Two Mechanics Can't Figure Out

puppyduks · August 5, 2010

2003 Yukon Denali, 146,000 miles.

Problem one is my demonic front a/c. Sometimes it bows, sometimes it doesn't. If you push random a/c buttons long enough it will blow a small amount of cold air. When I turn off the truck, it is still blowing or will start blowing. It seems the hotter the weather the less it wants to blow. Sometimes I get arctic force blowing, but that's only when it's not hot outside and don't need it. I never get to choose fan speed, if I touch the fan buttons it will abruptly stop blowing and refuse to come back on. When the truck is really hot from setting in the sun, no amount of button pushing can get it to blow. When it DOES blow, the air is always cold. The rear a/c blows fine. ASE mechanic (not GM dealer) told me it probably has a short because he checked all the hardware and it's all good. He quoted me $700+ to start because of the time needed to tear apart the dash to troubleshoot. Does this sound right?? I have a bad feeling about this. Should I shell out the $$ to him?

Problem two- I feel a vibration in my foot from the gas pedal sometimes, usually when I am moderately pressing on the gas. Two ASE mechanics and a transmission specialist have looked into this. All assure me the vehicle is working properly. They felt the vibration also on test-drive but couldn't figure out what it was.

I am a single working mom and have an infant daughter. I have no experience with auto repair. I tend to put my $$ into preventative maintenance to avoid big surprises and to provide a safe reliable vehicle for my baby.

GPSilverado · August 6, 2010

2003 Yukon Denali, 146,000 miles.

Problem one is my demonic front a/c. Sometimes it bows, sometimes it doesn't. If you push random a/c buttons long enough it will blow a small amount of cold air. When I turn off the truck, it is still blowing or will start blowing. It seems the hotter the weather the less it wants to blow. Sometimes I get arctic force blowing, but that's only when it's not hot outside and don't need it. I never get to choose fan speed, if I touch the fan buttons it will abruptly stop blowing and refuse to come back on. When the truck is really hot from setting in the sun, no amount of button pushing can get it to blow. When it DOES blow, the air is always cold. The rear a/c blows fine. ASE mechanic (not GM dealer) told me it probably has a short because he checked all the hardware and it's all good. He quoted me $700+ to start because of the time needed to tear apart the dash to troubleshoot. Does this sound right?? I have a bad feeling about this. Should I shell out the $$ to him?

Problem two- I feel a vibration in my foot from the gas pedal sometimes, usually when I am moderately pressing on the gas. Two ASE mechanics and a transmission specialist have looked into this. All assure me the vehicle is working properly. They felt the vibration also on test-drive but couldn't figure out what it was.

I am a single working mom and have an infant daughter. I have no experience with auto repair. I tend to put my $$ into preventative maintenance to avoid big surprises and to provide a safe reliable vehicle for my baby.

First off, I am not a GM Technician any longer, even though this is the "ask the gm technician" forum, but I don't like the sound of 700 to start.

I wouldn't take my truck to someone who 'thinks' it is a short, and wants 700 to start looking at it. Basically, it sounds like he doesn't understand the climate control system (assuming that it has climate control). That is the last guy you want tearing things apart. If he has a wiring diagram for it, and is actually planning to do real diagnostics, then maybe he would be OK. Are there any of the mechanics left in the area who worked for the dealership?

The vibration in the gas pedal may be something like an engine mount that is worn out. It could also be caused by an exhaust component touching the frame or cross-member when the engine is under load.

lhr360 · August 6, 2010

to fix your fan staying on and coming on when your vehicle is off that is a problem with the blower motor resistor block. you need to replace the resistor block, on your truck it is more like a module than a resistor block but if you tell them that they will figure out what it is

puppyduks · August 6, 2010

to fix your fan staying on and coming on when your vehicle is off that is a problem with the blower motor resistor block. you need to replace the resistor block, on your truck it is more like a module than a resistor block but if you tell them that they will figure out what it is

Thank you I will get that replaced. There is only one Chevy dealership in the town next to mine (about an hour away). They dissolved all the small GM dealerships here when they went bankrupt. We had a really good one here, too.

I still don't think it's a short, I kinda think it's too complicated a system for our small town mechanics to fix, since it's all computer controlled climate. I guess I will be taking it in to the Chevy dealership.

gmtech4 · August 7, 2010

very good idea.

i agree with SC ( no name silve lol) on this one

GPSilverado · August 8, 2010

very good idea.

i agree with SC ( no name silve lol) on this one

LOL, I just noticed that my name isn't there any longer...time to go see what happened to my profile. Thanks for pointing that out.

puppyduks · August 12, 2010

Just got it back from the dealership. $262 out the door and the a/c works great! It WAS the blower motor resistor thingy. Thanks guys! You saved me quite a few hundred dollars.