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2004 gmc envoy_slt_xl
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So, all of the sudden the A/C blower motor stopped working. Worked on the way to lunch, came out after lunch and nothing. Checked all the fuses and they are good. Replaced the blower motor resistor a couple of years ago. Any ideas what this could be? Is it simply that the blower motor suddenly failed?
 

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2004 gmc envoy_slt
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Which HVAC system do you have? Auto or manual (digital display or sliders)? Do any of the speeds work?

Could be any number of things, bad blower motor, bad resistor, bad resistor harness connector, wiring. You will need to do some visual inspection and voltage measurements.
 

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So, all of the sudden the A/C blower motor stopped working. Worked on the way to lunch, came out after lunch and nothing. Checked all the fuses and they are good. Replaced the blower motor resistor a couple of years ago. Any ideas what this could be? Is it simply that the blower motor suddenly failed?
 

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The so-called blower module is not really very sophisticated. If you've changed it already, it may not be the problem here. It's time for a 12v test light to follow the circuit(s) as they are energized and switched off.

Maybe the motor has pulled too many amps and fried the resistors again or the resistors themselves died. However - that said, the USUAL problem is a burnt switch or the spade connex to it going to the blower high speed wire.

The best way to eliminate this constant featured electrical faIlure of GM bad-ideas is to add a relay to the High Speed wire and add battery voltage to it via the relay that is turned ON by the High Speed wire that normally goes from the rotary switch to the 'resistor bank'.

Here normally in original design the voltage just goes around and not through the resistors in High Speed mode, but you can just cut off the wire from the High Speed switch position on the dahsboard switch assembly, and circumventing the resistor bank entirely - wire in the relay to take the load off the dash switch all together. If you do this correctly, you will still have all the lower speeds and a new circuit for the HIGH speed that won't cause any further harm to your system.

Easy - peasy!
 
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