wherzwaldo
(5000+ posts)
05/26/10 09:23 AM
Ford Expedition problems

I've got a 2001 Expedition whose rear windshield wiper and brake lights don't work. The wipers were an intermittent thing for a few months and then they stopped working altogether. (The rear windshield washer, rear defroster, and the power locks on the liftgate still work and always have, though.) I just noticed the brake lights this week and don't know if they've been acting up alongside the wipers or if this is just coincidental. The taillights themselves DO work when the lights are turned on.

I'm a total neophyte when it comes to cars, and I haven't started checking fuses or anything yet, but I've done a little research and would like someone to check my work. Rear wiper function is powered by a fuse and two relays (wiper up and wiper down) in the power distribution box under the hood, as well as another fuse under the dash. For the brake lights, I may be missing something, but they are not on any fuses/relays and are only controlled from a brake light switch which is also under the dash.

I know fuses are cheap and simple to replace, and apparently the brake light switch is also a fairly cheap/easy fix, but what about the relay? (I'm assuming it would only be the Wiper Up relay since it never gets past that point.) Do I have to disconnect the battery before I do any of this stuff?

accuratehorn
(10,000+ posts)
05/26/10 10:48 AM
Re: Ford Expedition problems

You don't have to disconnect the battery, there isn't enough current to worry about there.
Lots of times there are relays that are exactly the same part number in the relay box, and you can just switch the wiper relay with the power window or whatever relay to test it.
Same with fuses, if you can't see the filament, switch two that are the same amperage.
Then in rear hatch doors, a common failure is for the wires to break in the harness that goes between the body of the car and the door, because it gets flexed every time the door is opened. Also, in back if trailer wiring is present, especially add-on trailer light plugs, this can be the cause of a short back there.
But it could just be two separate problems like the rear wiper motor failed, then the brake light switch on your brake pedal failed, something like that.

wherzwaldo
(5000+ posts)
05/26/10 12:28 PM
Re: Ford Expedition problems

In reply to:

Then in rear hatch doors, a common failure is for the wires to break in the harness that goes between the body of the car and the door, because it gets flexed every time the door is opened.


I wondered about that since the wiper problem was intermittent. The windshield washer and the power lock still work, but I guess it's possible that only one of those wires shorted?

accuratehorn
(10,000+ posts)
05/26/10 01:37 PM
Re: Ford Expedition problems

Yes, one wire could be broken, or brittle or frayed and barely making a connection sometimes.

GarCiaRia
(250+ posts)
05/26/10 01:53 PM
Re: Ford Expedition problems

Brake light switch is a $30 part you can easily install yourself. It sits behind the brake pedal about a foot off the floorboard. Go order one from an auto part shop and they'll show you where its at. Plus there's lots of diagrams on the interwebs. if all the brake lights aren't working, then that's prolly your problem.

accuratehorn
(10,000+ posts)
05/26/10 03:25 PM
Re: Ford Expedition problems

Maybe his neighbor stole all the brake light bulbs after wherzwaldo complained about his kids walking across his lawn.

wherzwaldo
(5000+ posts)
05/26/10 03:41 PM
Re: Ford Expedition problems

Cool. I may stop by an AutoZone on the way home and pick one of those switches up.

Assuming the problem with the wiper is the electrical cord itself, how messy/difficult/expensive of a repair would that be? I ultimately don't care about that as much as the brake lights (my inspection sticker is expired) but it is annoying when it's raining.

accuratehorn
(10,000+ posts)
05/26/10 04:23 PM
Re: Ford Expedition problems

I don't know Ford prices, but it would be hard to guess without knowing what is wrong. It could need the wiper motor, and you might have to take some panels off to get at it to test it, so it could end up costing some bucks at a shop.

wherzwaldo
(5000+ posts)
05/26/10 05:19 PM
Re: Ford Expedition problems

OK, so I picked up the brake light switch on my way home. $13 + tax at Carquest. Disconnected the old switch, left it in place and hooked up the new one just to test, since it's a little tough to get to. Still nothing.

Do I need to have the switch mounted to the brake pedal assembly for it to work right? The new one is just kinda dangling above the brake pedal right now.

wherzwaldo
(5000+ posts)
05/26/10 10:15 PM
Re: Ford Expedition problems

OK, I don't think I installed it right... wasn't able to shift it out of P with the new switch installed, and I read that this is related to a complete failure of the switch. So, I will take another stab at it tomorrow.

accuratehorn
(10,000+ posts)
05/27/10 07:55 AM
Re: Ford Expedition problems

It might ground through the bracket it is mounted on, so it might have to be mounted to work. It also might be the wrong part or there may be a switch higher up that is the brake light switch.

wherzwaldo
(5000+ posts)
05/27/10 08:05 AM
Re: Ford Expedition problems

This is the forum post I found that led me in this direction, although it's for a different model year:
The Link

The part that I bought looks like that, but I suppose it could be for the wrong model year. I just told the guy at the counter what year/make/model I had and he gave me the part.