Front washer pump activates when headlight low/high beams are activated
So as the title says. NOTE: Front windshield washers. Vehicle does NOT have headlight washers. I started my diagnostics by monitoring the BCM PID's. When ever I activated low/high beams in any combination, the BCM does not see a request for the front washer pump. To me this indicates the short is not in the switch to BCM. So then I went to #7 15 amp fuse for the front washer pump located in the engine compartment. I remove the fuse and then activated the low/high beams. The pump did not turn on this time. This to me says the wiring from the fuse to washer pump is not shorted. I then gained access to the BCM and tripled checked my wiring to make sure I had the correct wires. I scoped washer pump relay control(ground controlled form BCM) at the BCM connector #X4 pin #15 orange wire. When I activated the low/high beams I did not have a short. At this point I called the fuse box located inside the engine bay. NOTE washer pump relay is a PCB mounted relay. It was installed and I got a call saying the problem still existed. At this point I was like impossible. So I went back and yes the problem was still there. I then retested everything and came to the same conclusion. I am tempted to have them get another one but I figured I'd ask for another set of eyes cause clearly I am not seeing something. I guess I could have a bad part but to me that is unlikely.
Edit. I just realized that ground G101 is a one way to the washer pump #7 15 amp fuse. IDK how I missed that but I will be checking that out tomorrow. Also I had checked all the connector under the fuse box no issues found.
It’s late here, didn’t look closely at wiring diagrams, is it possible this vehicle was in a fender bender and the body shop did something to a front harness?
I do know this was railroad truck and had some aftermarket stuff at one time. But I would think I would be seeing a short somewhere. I did do a visual inspection and didn't see anything jump out at me.
Phillip you don’t say if the screen is operating normally. I presume it has headlight washers, could the pump wiring or the pipe work be mixed up ? just a thought, regards Dave T…
No the front windshield washer. No headlight washers.
Edit. I just realized that ground G101 is a one way to the washer pump #7 15 amp fuse. I think you have answered the question. Is there a wiring diagram page that shows everything that sits on G101?