1989 F250 windshield wipers come on with truck shut off...

[GREASE FIRE]

my windshield wipers tend to stall while in operation, just momentarily, then start again. but when the truck is shut off, with key removed from ignition, they will turn on for one cycle every once in a while.
hopefully that was what was draining my batteries. So for now i have to disconnect the cables when the truck is off.
Could anyone please advise as to what needs to be replaced? can't be too many parts, either the switch (that's my guess) or the motor or perhaps there is a resistor as well.
thanks,
paul

 

[GREASE FIRE]

anyone?

 

[suv7734]

Questions:
When they 'stall' are they moving slowly or at regular speed?
Do you have pulse wipers?
When they cycle with the key off is it always only one cycle?

 

[GREASE FIRE]

Questions:
When they 'stall' are they moving slowly or at regular speed?
Do you have pulse wipers?
When they cycle with the key off is it always only one cycle?

as far as stalling during (intentional) use, it seems to happen at all speeds - but that was yesterday! today they worked fine while driving....so i am not too worried about that one for now.

when the truck is shut off, they come on for just one cycle, perhaps every 5 minutes or so. And that is with the key removed from the ignition...
so for now i just remove the battery cables so they don't run down my battery. And as soon as i go to attach the cables again the wipers kick on for one cycle.

my guess is that, since no one else here has this problem, it had to do with something the previous owner rigged up because the wipers are not supposed to have power coming to them at all unless the ignition is on - at least every other vehicle i have driven is that way. On this truck i can turn them on at all speeds with the ignition off.
hopefully the problem is at the switch.
any other ideas appreciated.
thanks,
Paul

 

[Agnem]

The wiper motor always has 12 volts going to it, just like the heater blower. It's the ground path that is being controlled. So, if you get a short to ground, it will run. I'd suspect a problem with the switch that is on the cam in the wiper motor.

 

[GREASE FIRE]

how to access wiper motor?

The wiper motor always has 12 volts going to it, just like the heater blower. It's the ground path that is being controlled. So, if you get a short to ground, it will run. I'd suspect a problem with the switch that is on the cam in the wiper motor.

thanks for your help.
do you have to remove the dash to access the wiper motor? or can it be accessed from under the hood?
thanks,
Paul

 

[suv7734]

Here's a pretty good description of the procedure.

 

[GREASE FIRE]

The wiper motor always has 12 volts going to it, just like the heater blower. It's the ground path that is being controlled. So, if you get a short to ground, it will run. I'd suspect a problem with the switch that is on the cam in the wiper motor.

i figured out that the switch on the dash is not the problem. So if it is the switch on the cam in the wiper motor, does that mean the motor has to be replaced or is the switch you refer to something that could be replaced individually?
thanks,
paul

 

[suv7734]

The cam is part of the "park" system in that the wipers will return to the "park" (bottom) position when the switch is turned off. Do you have pulse wipers because that can be part of the problem.

 

[GREASE FIRE]

yes, i think they are pulse wipers. there are three speeds to the wipers, then when the dial switch is turned all the way CC it is supposed to turn them off; then you can vary the speed of them by turning it a little bit CW - there is a range of variation in that first position. Does that mean they are pulse wipers then?
thanks,
paul

 

[Jake S.]

Delay wipers are off at 12o'clock, low is one notch CW, high is two notch CW. Delay is turn CCW from the 12 o'clock off.

 

[GREASE FIRE]

Delay wipers are off at 12o'clock, low is one notch CW, high is two notch CW. Delay is turn CCW from the 12 o'clock off.

that's actually how mine work - just a better description than the one i attemepted.
now i just have to figure out how to fix them...
thanks,
paul

 

[Joe Mc]

On earlier models the delay module sits over the parking brake pedal, letting the foot pedal slam up when released has caused problems inside the module. If yours is mounted near the parking brake, open and check for broken solder joints or damage to the circuit board. I have heard that on later models Ford moved this box, but I don't know what year.