2012 prostar+ bunk fan

Hey all. My bunk blower motor has stopped working. I have verified the motor will work when I put 12 volts to it. I replaced the blower motor controller. When trying to use the dash switch it comes up on the screen that it is at half speed but will not adjust. Where do I start?

I have power the the red wire from the controller to the fan motor. I do not have ground on the black wire. If I ground the black wire fan runs at full speed.

 

I have a climacab apu which is separate. I haven't seen anything that says no-idle.

If the vin would help it is 3HSDJSJR1CN547398
Thanks

 

Is there a way to test the dash control module?

It says B E H R #P3728001

thanks

 

Here is a picture of it. My local dealer called it a dash control module. It turned out to be the issue. The original one lost connection with the BCM.

It works as it should now