My son’s 250 diesel truck will stall if you turn on the windshield wipers while driving in the rain. He has had it looked at several times but unable to locate the problem. Any ideas?
My guess is a short from wiper wiring to ignition switch
So how do you fix it? Replace the wiring.
I’d suggest installing a redundant ground from the wiper motor to the battery.
One way is to visually follow wiper wiring starting at switch as far as you can see. Look for pinched or damaged wires. Then the same for the ignition. You may not find it. Another way is to get a wiring schematic and then you can see what does what. Maybe the wiper switch can short in the switch itself. The diagram knows. It can tell you where each wire starts and stops so you know which ones to check. You could find a shop to do the work. The place I worked for would not have handed you the keys and said I can’t figure it out. We would have found the problem and fixed it with authorization. Sombody can do it. Try again.
OP, I was interested in your problem, so I googled “f250 wipers stall engine” and found some useful info. Apparently the wiper motor, fuel pump, and lights share the same ground. They suggested cleaning the ground, changing the wiper motor, and changing the fuel pump, but the wiper relay being replaced is what ultimately fixed it. Type what I did into your browser and the discussion I’m referring to is the first thing that comes up. There’s also a wiring diagram and description of the location of the possible problematic ground on that site. From the sounds of it, locating and cleaning that ground is the first step. Good luck.
There’s three wires involved w/power the ww motor. colored y/r, w, & db/o. the common for those wires is bk/pk. measure the voltage on those three pairs, for example start with the voltage (y/r , common ). do a look-see, do you notice anything unusual as the ww goes through its cycles? do the same for the other two wires and common. nothing unusual? next measure between the dg and bk wires. that’s the run/park switch. do you notice anything unusual there as the ww goes through its cycles?
Thanks for the info.
Let us know what you find out there OP. WW involvement with engine stall is definitely a weird one.