Why won’t the blower motor run?

ID Status Date Year Make Model Transmission Type A/C Controls Public/Private
#14249 Closed 2006 Chevrolet Silverado LT 2500HD public

The blower motor stayed running on high speed, even with the key off. I replaced the resister module. Now, the motor will not run. I removed the motor from the plastic housing and blew out the dirt and carbon dust. I have 12 volts to the motor plug. With the motor sitting on the floor, engine running, the motor will turn 1/4 turn and stop. After about 30 seconds it will turn another 1/4 turn and stop. If I turn the fan by hand, when the motor starts to turn again it starts and runs ok. Start surge amps is 18. Resistance from terminal to terminal is 0.8 ohms. There is some brush and commutator wear. HELP!


From your description I am assuming you have auto controls in your truck. What is the part number of the replacement part? What color is it?

Yes , it is ATC.
AC Blower Control Module – Replaces# 1580567, 93803636, 52413530, 89018778, 4P1516 – Fits Chevy Silverado, Trailblazer, Cadillac Escalade, GMC Envoy, Sierra, Buick Rainier – AC Heater Blower Resistor SKU: GWA185
Sold by: GWA Auto Parts. It is black, and purchased from Amazon.


The early replacement black modules were very temperamental and were quickly replaced with gray  modules. I am including a link to an article I did a few years ago that may help clear things up for you.


So you don’t believe that the starter is at fault? I know the starting amps is within specs, but I wasn’t sure about the resistance value through the brushes.


I recommend installing the updated GM/ ACDelco part number 15-81773.

Trying to eliminate every possible thing I can, before filing a warranty claim for the module, this morning I checked for voltage to the module. With the key off, there was 12 volts? I re-installed the blower motor and started the truck. Everything worked! until I shut the truck off, and restarted it. Now it doesn’t work. I guess I’ll have to order the updated module. Should there be power to the module with the key off?

I have ordered the ACDelco part number 15-81773. I was hoping you could answer the question, whether there should be power to the module with the key off, or not? Thank you.


There is constant power on the red wire, constant ground on the black wire and the small purple/white wire will have either 5 or 12 volts depending on which module part number it is attached to.  All of this information is in the article that I supplied a link to earlier and there are multiple links within that article to even more test information.

Thank you very much for all your help. I won’t have the new module until Monday. If I still have issues, I’ll start another ticket.

I got the ACDelco 15-81773 A/C Power Module today, and installed it. Everything works perfect! Thanks for your help.

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