Rear blower motor not working

Just to be sure you replaced the aux blower motor control module and not the one in the front.

If you did, then we need to check two more things.

First, we need to check the power at the blower motor and confirm you are getting 12-volts when it is on high.

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

Then we need to check the grounds by using the 12-volt source and then both grounds and your meter should read 12-volts.

If it does, then we need to move to the control processor. We need to check and find out if there are 12-volts on the B+ circuit and then the speed control should change as you increase the speed.

Lastly, we need to check this ground the same as the other.

Please run through this and let us know what you find and then we can go from there to find out the next steps.

Just to be sure, you are jumping a wire from the motor to ground and the motor runs.

Can you confirm what terminal you are jumping this wire from on the motor to ground?

I am attaching the blower motor connector below. Thanks

So, if you provided ground and the motor ran then the module is not grounding the motor. That means that the module would be the issue.

Is that what you replaced?

Yeah. I would give that a shot.

Looking at the wires at the control module, which I know you said you checked and provided but I just want to make sure.

On the speed control wire (B), that is going to vary depending on what you put the switch on.

The B+ wire (C) you should have 12 volts.

The ground (A) should be ground so use C to check this and your meter should read 12 volts when on C and A.

Then the black wire going to the motor is your ground for the motor.

The purple wire going to the motor is your voltage supply and will vary based on the switch setting.

Take a look at the diagram again and if this is what you have except for the ground coming from the motor back to the module then the module is the issue.

Test leads getting hot points to a faulty ground.

However, I thought you said that it only ran when applying ground.

Meaning it has 12 volts but no ground.

But if you are running power from the lighter then that would mean we don't have power.

So, let's take a step back.

Can you turn the blower motor on high and go to the module and tell me each voltage on the wire?

Check this by a known good ground for your black lead of your meter and then touch each wire terminal with the red lead.

Great question. Back probe the connector with the entire circuits intact. So, everything is connected so that we can see what the system is doing.

Thanks. We will wait to hear back.

Okay. That keeps us focused on the ground from the module to the motor. So, the black wire that is connecting the motor back to the module should show ground as all the other readings are correct.

So, this means we need to ohm out the wire itself.

Take a look at the diagram below. Disconnect both connectors (module and motor) and we need to measure the resistance of the wire itself from connector to connector.

You put your meter on ohms and then just touch one terminal to each end of this wire and tell me what the resistance is.

E-M(+) pillar ground>E=14.84v, this must be 0 volts. Can you run a ground wire to this one first to see if the system starts working?