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

Problem Description and Possible Solution

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.

Problem Data
RepairPal Verified
Average mileage: 117,794 (81,000–149,768)
6 model years affected: 1998, 2000, 2001, 2002, more2003, 2004
16 people reported this problem
Viewing 1 - 6 of 6 comments
HVAC Blower motor works at 1,2,3 and fails on number 4 setting
Same problem here works on all but 4.
Fan makes screeching noise when running. Has not been fixed yet
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.