Loss of One or More HVAC Blower Motor Speeds on GMC Sonoma

The HVAC blower motor may stop working at one or more speeds due to a faulty blower motor resistor block. Our technicians recommend to confirm the resistor is at fault by first checking the operation of the switch.

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Average mileage: 111,400 (81,000–145,000)
5 model years affected: 2000, 2001, 2002, 2003, more2004
10 people reported this problem
4 people shared problem details
2000 GMC Sonoma145,000
HVAC Blower motor works at 1,2,3 and fails on number 4 setting
2001 GMC Sonoma100,000
Third time it has blown. Seems they last less than a year. Blew out totally on all speeds twice. This last time it was just the high speed. Replaced the resister all 3 times. They are guaranteed for a year. Lost last receipt. Paid for current replacement ($20) so I am waiting a couple of months and going to turn in my bad one for a new one. That way, I will have one on hand to change next time as this seems to be an ongoing issue. At least they are easy to access to change. This time though, I went into the fuse panels and pulled and applied dielectric grease to all fuses. Perhaps weak/ faulty-corroded connections? Probably not but nothing to loose. Seems resister craps out when changing blower speeds or switching off/ on. Too bad. This thing has a kick ass high speed blower system. Is it being caused by a voltage spike from the blower speed switch? Dunno.
It is as if the AC stops working. But this problem shows up in the middle of summer when I am using the AC the most. I just stop getting cool air and then there is no air blowing through the vents at all. Not much I can do but turn everything off and roll the windows down.
Setting I and II wouldn't work. Replace Resistor to fix.
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