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Tim West
Tim West, ASE Certified Technician
Category: Chevy
Satisfied Customers: 4638
Experience:  ASE Certified Service manager of Firestone
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2001 suburban: air conditioner..blowing hot air..through defrost vents

Customer Question

My heat and air stopped working on my 2001 suburban after the air conditioner starting blowing hot air. Now the defrost, heat, and air fan does not work at all. Hot air flows up through defrost vents, but that's from the engine, no fan blowing. We changed out the fuses, and still did not work.
Submitted: 7 years ago.
Category: Chevy
Expert:  Tim West replied 7 years ago.
Thanks for visiting
Sounds like you have a bad blower motor or blower resistor.
If the blower works on high only, you have a bad resistor. If the blower motor is inop all the time, you probably have a bad blower motor but let's test it.

1. Check for HVAC control module codes.

2. Verify B+ to the blower motor control processor (module), Red wire, pin A.

3. Verify ground to the blower motor control processor, Black wire, pin C.

4. Verify a pulsing ground to the blower motor control processor, Purple/White wire, pin B. A direct ground of this circuit should allow the blower to function at HI speed.

For replacment info see
5. Jumper the Red to Purple and Black to Black at the blower motor control processor.

6. Check that the blower motor runs OK, high speed.

7. If the blower runs OK, replace the blower motor control processor.

8. If the blower seems to operate slowly or is noisy, replace the blower motor and the blower motor control processor, see bulletin #04-01-39-009C.

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