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2003 chevy trailblazer_lt_ext
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Discussion Starter · #1 ·
Help TB family,

My rear air is blowing ice cold, my front air doesn't blow at all. I have an 03 TB EXT with 111,000 miles. I replaced the fan clutch about 3 weeks ago and now I have the A/C problem. Any ideas would be helpful. I've checked the mini-fuse in the engine compartment and the fuse under the rear chair, they're both good. My next step is to check the blower motor to see if I'm getting power at the motor.
 

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2003 chevy trailblazer_lt_ext
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25 Posts
Discussion Starter · #2 ·
Update to problem

It also doesn't work with heat so I'm guessing it's the blower motor not working. I didn't check power because it looked like a lot of work at 8 PM to disconnect the airbag system and I'm not ready to replace the part. I'm going to save it for the weekend when I have the time to do the job right.
 

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2009 chevy
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6,431 Posts
It's definitely in the blower circuit. You didn't say if it was the digital system, or the manual system. You list a LT truck, so I'll guess it's digital.

The digital system uses 1 fuse #35 (I think) under the hood.

There is a digital speed control module, mounted near the blower motor (under dash, behind the glove box), it could be bad.

And, of course the blower motor as well.
 

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2003 chevy trailblazer_lt_ext
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Discussion Starter · #4 ·
Front Blower Inop

I'm sorry, it's the manual system. I've checked all the HVAC fuses and they're all good. I'll go under the dash tomorrow when I have more time. It's the NBA Playoffs and the local team (Spurs) should be losing they're second game tonight.
 

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I'm sorry, it's the manual system.
That actually helps to track the problem.
The major difference is that the manual system uses 2 fuses for blower speed. One fuse for speed 5 and the 2nd fuse for all other speeds.

This should eliminate the fuses. Look at the speed control module to see if it's burnt, if it looks fine, the problem is probably the motor.
 

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Discussion Starter · #6 ·
A/C Problem Update

I've pulled the connector off the resistor. I have 11 Volts in all positions except position 5 where I have less than 1 volt. The motor ohms out good. I'm at wits end on whether it's the motor or the resistor. I've checked the ground to the car and it's also good. I'm going to take the blower motor and my multi-meter to Autozone and check the resistance on a new one.
 

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Discussion Starter · #7 ·
A/C Problem Fixed

The A/C problem is fixed, I changed out the blower motor resistor unit after testing the motor at Autozone. $27.00 later, the wife is happy she has her A/C back.
 
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