Rear HVAC fan not running?

JASON SHEPARD

MEMBER
2019 CHEVROLET TRAVERSE
3.6L
V6
4WD
AUTOMATIC
56,000 MILES

Hi all, my rear HVAC fan is not running at all.

Here is what I know:

Fan is getting 12-volts continuously and spins when bench testing. It appears to not be getting ground. No easy way to test PWM with standard multimeter. Thinking is the Main HAVC control module behind head unit. Already replaced rear fan control module twice with no results. My thought is PWM is stuck open and not sending any ground to fan.

Thoughts?

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

When you check for power to the motor, is it via a brown wire with a gray tracer? Also, is there a ground path (low reference) on the blue wire with a black tracer? If not and you have already replaced the control module twice, disconnect the module and check the black wire for continuity to ground.

The ground is located behind the right, rear wheel well. It is ground number 402 (G402). See below.

If you look below, pic 1 is a closeup of the aux blower motor circuit. Pics 2 - 5 are the schematic. The body ground for the module needs to be functional. Check that for me.

Let me know what you find.

Take care,

joe

See pics below.

Images (Click to make bigger)