Washer pump wiring help
 

Hey guys I need some help. The washer pump on my 66 doesn't work from the switch. I looked under the dash and found a wire spliced. The yellow wire is spliced into a grey one. Any idea what's going on here. Thank you

Re: Washer pump wiring help
 

bump

Re: Washer pump wiring help
 

The yellow wires are the +12V feeds to the wiper motor and washer pump solenoid.

I believe these trucks originally used a "4 terminal" wiper motor that has 2 power terminals. One power terminal connects to the yellow feed wire from the dash harness. The other power terminal connects to a short yellow jumper wire that feeds power on to the washer pump. The dark blue wire on the washer pump is a switched ground. Pushing the washer button on the dash switch completes the circuit to ground (via that dark blue wire) to activate the solenoid that engages the pumping mechanism.

Some years had a very similar looking "3 terminal" wiper motor with only 1 power terminal. Those used a "daisy chain" type configuration to connect the yellow power feed wire to both the motor and pump.

I'm not sure what's up with that yellow to grey wire splice in your truck. But it's possible that someone put a "3 terminal" wiper motor in place of a "4 terminal" motor and they couldn't figure out how to hook up the washer. If that's the case, they should have spliced that yellow wire from the pump to the yellow wire going to the motor.

Grey is the color code used for the dash light circuit. So if that grey wire is factory, it looks like they spliced the washer pump to the dash lights ... not a good power source for that since the voltage on the grey wire can be lowered (by rotating the headlight knob) to dim the dash lights.

Re: Washer pump wiring help
 

Thank you, I will look into it more!