I recently purchased a used 1999 Ford Expedition with about 94K miles on it ... overall, it's in pretty good shape for the miles & price ($7K). My first Ford truck!

While it does need some undercarriage work (ball joints, stab bars and rear axle grease seal replaced), one thing that I discovered was that the rear wiper doesn't work. The front wipers work fine, as does rest of the functions on the console switch stem.

Is this a common problem? I seem to recall that Ford had some trouble with the wipers on the F150 platforms.

Any suggestions on how to fix this or where to isolate the problem?

Thanks!

 

Seems to be a common problem with expeditions,,, At 153,000 miles my 97 is ready for its 4th rear wiper motor. The first two were Ford under warranty. The third was a NAPA , replaced by me.
Something you might try, and its what I do now,, give the wiper arm a bump upwards with your hand.. I can do this with mine and it will work for the day..
I think I am going to take this one apart and see if there is a bad spot in the motor that I can clean.

Good Luck

 

Motors are cheap, and if you get one from Advance Auto, they have a lifetime warranty.

As for things to check, you'll need ot remove the trim panel to access the motor. If you unplug it, with the switch on, if you connect a DMM between the bk/lb and w/og terminals on the plug, and set the switch to high, you should see voltage in one direction than the other (as though the system is cycling). If you don't, check both of those two pins individually against a known good chassis ground, and see if you're getting power. If you're getting power to one and not the other, you likely have a bad or sticking relay in the battery junction box under the hood.

Ordinarily both relays are grounded and the motor doesn't move. When it comes out of park, it bumps the wiper-up relay. Then, it sends power from the wiper up relay, through the motor, and back to ground through the wiper down relay for a second (or however long it takes for the wiper to move). Then the down relay is energized and the power reverses the motor and grounds through the up relay. If one of those relays sticks in either position, the circuit is open and nothing moves.

Now, if you check everything, and you've got power, replace the motor. Not a big job at all.

Check it out and let us know what you find.

 

The motors are usually OK. It's the nylon gears that get eat up. R&R takes about 1/2 houe. New motors are about $40.00 at the parts store.