I'm sure this question has probably been asked but I couldn't find it so I'm hear to ask it now. I'm not getting full power to my wiper switch. Only one wire which im assuming comes from the ignition has power but its max of .40v instead of the 12v it should have. I'm truly lost, I've replaced the wiper switch just as a future part I won't have to worry about. FYI it is a 1980 f250 custom with the 351m and a 4 speed

 

Did they ever work?
Delay or non-delay?
Installed a new fuse?
Dave ----

 

When you are measuring voltage, are you putting the negative lead of the meter on the motor assembly or somewhere else on the truck? A lot of these wiper motors are mounted in rubber mounts to lessen the noise they make, so that requires a ground strap from the motor to the firewall. Sometimes this wire or strap will break.

 

I got it from a junkyard thats been sitting for 5 years so idk if they every worked.
I also don't have the fuse location diagram so idek if the fuse is the right size or even what one it is
they are the regular wipers high, low, and park

 

OK let me see if I can find a fuse box layout and the size of the fuse and maybe a wiring diagram so you can test some things.
Dave ----

 

if u could find one thatd help a lot

 

1981 wiring diagrams here. 1980 had some differences, but hopefully this is close enough. See page 60 for the wipers:

Windshield Wiper/Washer - Gary's Garagemahal (the Bullnose bible)


Note the wipers do not have a fuse. There's a circuit breaker inside the control switch.

Push the wiper switch in and see if the washer spray motor runs. If so, that means power is reaching the switch.

A common problem is the run/park switch inside the motor gearbox. If this fails, the motor won't run.

As previously mentioned, make sure the motor/gearbox is properly grounded. IIRC, it's grounded via one of the mounting bolts to get around the insulated grommets.

If you have to remove the motor/gearbox, do this simple modification to save yourself a LOT of work:

https://www.ford-trucks.com/forums/1...or-change.html

 

In the diagram below, notice how the motor is fed two power sources. The red wire and one of the other wires depending in what speed you select.

 

Thanks guys for the helping hand
Dave ----