blower not working on all speeds

[MoHawk]

I have a 2004 Trailblazer EXT 4x4. My blower is not working on all speeds. It doesn't matter if I am in vent, heat or a/c mode. First speed 2 quit working and then speed 1 quit working. 3 - 5 still work. Also when I have a/c on and I'm at a stoplight idle the engine seems to start to run rough and feels like it wants to quit (a rumble feeling) and I hear air noises (hard to describe - like a something trying to cycle) in the floor area of the passenger side front.

Probably more than one thing going on....thoughts?

 

[The_Roadie]

Welcome! I answered your rear blower question in your other thread. How long have you had the truck, how many miles, any other maintenance history, and (I'm guessing) did you recently change, totally discharge or disconnect your battery? The running rough symptom is 97% chance of being triggered by this.

Blower speed control failures are almost always the "resistor pack": http://gmtnation.com/f93/how-replace-blower-motor-resistor-pack-connector-pigtail-3004/

Running rough (erratic idle) especially when the AC compressor is on is due to a dirty throttle body. Many members remove and clean theirs every 30K miles. GM design error on the PCV system of the I6.
http://gmtnation.com/f25/how-clean-4-2-inline-6-throttle-body-221/

 

[MoHawk]

Welcome! I answered your rear blower question in your other thread. How long have you had the truck, how many miles, any other maintenance history, and (I'm guessing) did you recently change, totally discharge or disconnect your battery? The running rough symptom is 97% chance of being triggered by this.

Blower speed control failures are almost always the "resistor pack": http://gmtnation.com/f93/how-replace-blower-motor-resistor-pack-connector-pigtail-3004/

Running rough (erratic idle) especially when the AC compressor is on is due to a dirty throttle body. Many members remove and clean theirs every 30K miles. GM design error on the PCV system of the I6.
http://gmtnation.com/f25/how-clean-4-2-inline-6-throttle-body-221/

The truck has 133K miles on it and yes I recently had a battery discharge. I don't know the entire history of the car since I bought it with about 80K on it and I took it into the shop for a full tune up at that time (not sure all that was done just asked for the whole 80K mile work up). Since owning the vehicle, I have completed normal routine maintenance with oil and filter changes and recently replaced the A/C compressor (1 1/2 years ago) and the water pump.

 

[The_Roadie]

Thx. You could fill out your vehicle profile to save some time in the future.

One thing I always remind 4WD owners is to make EXTRA certain that the transfer case fluid (only use GM Auto Trac II) gets changed every 50K. It's a surprisingly short interval. And test the 4WD system every month to make sure there's no surprises when you need it the most.

 

[MoHawk]

Thx. You could fill out your vehicle profile to save some time in the future.

One thing I always remind 4WD owners is to make EXTRA certain that the transfer case fluid (only use GM Auto Trac II) gets changed every 50K. It's a surprisingly short interval. And test the 4WD system every month to make sure there's no surprises when you need it the most.

Thanks for the advice. I will make sure that happens. I know I used 4wd a few times this winter and all was working. I also updated my profile.

 

[triz]

You might have debris in the blower fan which will seriously reduce the air. I removed it (like 6 or screws) and found it was full of leaves. I shopvac-ed it out put it back and the AC blew strong again. I always try and keep the exterior vents clean but sometimes those damn leaves make it thru the system.