2012 workstar rear signal issue

Here is an issue that I have exhausted my ideas hoping the IH professionals have run into this before.
I actually have 2 issues which may or may not be connected and mainly concerned with the first issue.
Its a 2012 workstar plow truck with a dump body. I have lost rear signal and brake power (signal and brake on same power like small autos) I have working right front right signal and hood signal. There is a large junction box on the side of dump body and if I jump power to the right signal post lights will work so I know the rear circuit is okay. If I disconnect the cab connector and connect a jumper between the two parts of the cab connector the signals will work fine so I know the circuit from cab to rear right signals is okay. The problem happens when I reconnect the firewall plug then I loose my signal power. Disconnect and put test light on firewall plug pin and there will be no power. If I cycle the key I will again regain signal power. I suspected the body controller that is mounted on the left side kick panel to be the fault and swapped with another controller also out of a 2012 but problem existed. Also replaced signal stat no change. The thing that confuses me is the key acts like a reset is there another body controller that plays a part?

The other issue is when the key is on and the wipers are turned on the clearance lights come on even though the headlight switch is off. If the headlight switch is turned on and off again the lights will go out and the wipers will stay on until the wiper switch is turned off.

Any info is appreciated

 

Thanks Heavyd great advise as usual. The light with wiper makes sense I have just never noticed it before and our other trucks do not do it so they must not be programmed to do it. I agree with the theory but might try to turn the feature off just to prevent confusion in future. Its a plow truck and our drivers run the lights as habit most of the time but its good to know its a programmable feature. As far as the signals I have a few more ideas to check. Just needed to step away from it and get some other ideas so I will see about finding issue tomorrow. Thanks I will report findings.