Rear Blower motor not working

Hello,

Can you tell me when you replace the rear motor and module did you use AC Delco? Because it sounds like both are bad now which could just be a coincidence. here is a guide to help you test the blower motor by putting 12 volts to them and the front and rear blower motor wiring with a guide so you can do some testing and be able to see how the system works:

https://www.2carpros.com/articles/blower-fan-motor-works-on-high-speed-only

and

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

Thanks for the response. Since the front failed as well, I took from the rear, the brand new module and both the new and old blower to the front to test and all worked, as did the front module. So answer to the front was a new blower, bought that and all good there.

So now my primary issue is, in the rear, I have a good module, a good blower but cannot get them to work. I did take the ground and power and connected them to the harness of the blower and bypass the module, nothing! I found there is a screw where the black wire is grounded to. If I put my black probe on that, and my red probe on the power, I am getting like 52 mV, this is only .052 volts, this cannot be right.

The black wire need to be grounded, can you add a ground to see if the system works? The orange wire has power when the key is on yes?

Correct, orange wire is getting 12volts. The black wire is grounded to a bolt stud behind one of the panels.

Okay, that leaves the auxiliary HVAC control module which is mounted to the top of the HVAC unit in the rear.

This should be the part Control Module 89018778 $134.70

Check out the diagrams (below). Please let us know what happens.

Yes sir, you will see from above I have replaced this already and even tested in the front and found it to be a working new unit.

Interesting development. I bought a probe and found I was only getting 1 volt. There was another orange wire getting 12v, so I tied them together and it started to run then died and not getting power to those wires now. Checked RR fuse and tested fine. Ugh

Ken, here is where I am at now. 2 orange wires in the rear, one for control module, the other goes to the black box between the actuators.

I am not getting 12v on either orange. I traced one using a cable toner to the driver side fuse and the other to the fuse box under the hood, but fuses are good! What do you suggest?

Under the hood do you have power at the RR HVAC fuse? check to make sure the fuse holder is not melted. Let me know

I did a light test successfully. Is that enough or should I use a multimeter?

So that fuse is what powers the orange wires, if the fuse has power and the wires don't there must be a break in the wiring/connections issue.check out the wiring diagrams above and use your test light to see where you lose power.

Fixed problem following this YouTube:

https://youtu.be/Z9dWLM51gkQ

Good find on that one. Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.