Blower motor doesn’t work or won’t change speeds
GM has issued a service bulletin #PIT5343 to address a situation where the Blower Motor doesn’t work at startup or won’t change speeds at startup. The bulletin affects the following vehicles:
2014 Chevrolet Silverado 1500
2015 Chevrolet Silverado, Colorado
2014 GMC Sierra 1500
2015 GMC Sierra, Canyon
With Manual HVAC (RPO C67 or C42)
How the blower motor problem appears
If you own one of the vehicles listed above and notice that the blower motor doesn’t work when you start the engine, or the blower motor won’t change speeds, do NOT replace the blower motor, switches or resistor.
This is a software issue that can lock up the HVAC control head if you follow this routine:
1. Engine is running and
2. Blower motor is running and
3. The HVAC mode is Defrost and the defrost light is on and
4. You turn the Blower Motor to the Off position and then
5. Turn off the Defrost mode and then
6. Shut off the vehicle.
After following this routine, the blower motor won’t run when you restart and it won’t respond if you try to change blower motor speeds.
You can force the blower motor to work by choosing any other mode and rotating the blower motor knob. Or, rotate the blower motor knob.
To fix the problem permanently, have the dealer or an independent repair shop reprogram the HVAC control with an updated software version.
©, 2017 Rick MuscoplatPosted on by Rick Muscoplat