Question about 2000 Chevrolet Blazer

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2000 CHEVY BLAZER NO HVAC( RE-POST w/MORE DETAIL)

The whole hvac system stopped working . Mechanic said " bad blower module" I replaced that ...no change. Since then I have bypassed all modules, fuses and such to the blower motor ,which works fine when supplied w/ direct power. I have checked the hvac fuse and all others, they are all fine. At this point I have the Computer Climate Control unit removed from the dash and have tested the wiring harness which feeds it. With info found on-line I tested for voltage on specific pin numbers of the harness. With the info i have, it seems to check out good. So this leads me to believe that its the CCC unit which is bad. I'm still not sure but it would make sense that with a bad control unit the proper voltage would never make it to the blower module/motor. So that's where i'm at. Any suggestions are appreciated. I'm hoping maybe I just overlooked a relay somewhere.

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Replace the control unit this should solve your problem

Posted on Mar 08, 2009

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Circuit/System Description
The auxiliary blower motor is a variable speed fan. The HVAC control module controls the fan speed by sending a pulse width modulated signal to the auxiliary blower motor control module. The auxiliary blower motor control module varies the duty cycle across the auxiliary blower motor in relation to the pulse width modulated signal. The auxiliary blower motor speed can be adjusted from 10 percent to 90 percent duty cycle (PWM), 90 percent is high speed fan.
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Your not going to like to hear this , but you'll need to take the dash apart !
Blower Motor Resistor Replacement
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1
HVAC Module Assembly Nut (Qty: 5)
Tip
Tighten the nuts in sequence.
Tighten
9 N?·m (80 lb in)
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1 Answer

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