Last friday I bought my sisters 99 v6 Cougar which she had been driving for the past 6 months. I drove it a little over the weekend and noticed something odd that Id never seen before on any of the 5 cars Id previously owned. Id be driving and when Id need to brake, Id often get the windshield wipers coming on by themselves for a few seconds. It doesnt seem to happen a lot, but enough to annoy me. Either she neglected to tell me about that problem, or its something new going on with it.
The car is still in great shape and only has 80k miles on it, so Im not dealing with a POS car here.
Does anyone know what would cause the wipers to automatically turn on like that?


Edited by: wolfbiker99

Weird. Does the car have a rear wiper? And if so, does it work and are all the wipers on the signal arm? And does the rear defroster work? They may sound like strange ?''s but I had a similar situation once. Let me know. You could unplug the brake light switch and let me know what happens with that, too.

Yeah it has a rear wiper and it does work, but I dont know about the rear defroster yet. Im assuming it does work though. But the rear wiper is on the same arm as the front wipers. You have to push it in to turn the rear one on.
Where is the brake light switch located? Wouldnt unplugging it make the brake lights not work?

You did say it only occurs when you depress the brake pedal, right?

Yeah thats right. Only when I press the brake pedal.

Well there has to be a short circuit or bad ground. Unpluggging the brake light switch(under dash/rear of brake arm)should surely stop it. But curing it is a different story. I asked about the rear wiper/defroster because I had a car that I was working on a couple yrs. ago. Whenever the lady hit the brakes, the wipers(rear one, too) would come on as did the rear defroster. After a afternoon of trying to figure this out, I discovered the rear defroster was unplugged on the hatch. The plug also powered the rear wiper. So when she hit the brakes everything went whacko because the third brake light on the rear window became ungrounded because the switch was unplugged. In short, that plug was part of a larger circuit loop, which became a open loop when it was unplugged. Do you have a multimeter, test light, etc. on hand?

I dont where I am at the moment. I have one in my tool box but its at my folks place. I can pick that up either tomorrow afternoon or this weekend.
Where would you suggest I start checking with a multimeter?

If the rear wiper is in the on position when you hit the brakes, does it move w/the fronts? Did you unplug/remove the brake light switch? I think the switch went bad and is shorting out causing this strange reaction.

The rear one hasnt moved when the front ones have.
Like I said, it doesnt happen every time I hit the brakes, but only sometimes. I drove last night for about 45 minutes and it only happened once, but a few days ago I drove for 15 minutes and it did it 4 times. Its pretty random.
I havent removed the switch yet, but if it were the switch, where can I get a replacement one?

Edited by: wolfbiker99

At your local parts store. If you want genuine Ford parts then you must go to the dealership and pay an arm and a leg. That''s up to you if you want to spend the $$$$, but I would go to NAPA, etc. Did you unplug it yet? Might as well and see what happens. It''s not like you have to risk getting a ticket for no brake lights. Just sit in your driveway and keep depressing the brake pedal and see what transpires. I''m guessing the wipers are not going to move. Let me know.

I bought a new switch for $6 today and replaced it. I figured with it being that cheap it was worth trying. Tonight on my drive home the wipers went off again.
I was almost thinking it had something to do with having the cruise control on, but I had it happen with cruise control off too.
Its just very very random. I''ve driven around 150 miles in the past week in that car in there were times when it didnt do it at all the whole time the car was running, and then there were times it did it about every other time I would tap the brakes while driving. A few times I even had the wipers come on when first starting up the car.
I just pulled the fuse for the wipers though. I''ll leave it out til I can figure out what causes the wipers to turn themselves on. I figure I should be alright, since I rarely need them anyway. Rain-x makes it ok to do that.

Starting to think there is something shorting out in the arm that controls the signals, wipers, cruise, etc. When you hit the brakes, electicity flows through the rear brake lights which are on the same circuit as the rear signal lights, which are all tied to the arm on the steering column. That would explain the cruise possibility. See where I''''m going? I would change the arm if possible. Let me know. Maybe get a junkyard one to be sure. I think we got it now.Edited by: conan312

You could be right. It would make sense if it was something in that armIll call around at some yards and see what I can get.

But I just remembered the signal arm is on the left, and the wiper arm is on the right, so they arent together. Could it be deeper in the steering column?

Just when I think I''ve got it licked, you remind me of a minor detail that majorly flaws my diagnosis. I''m still confident it''s a short in the arm though. Do both column arms feel firm and sturdy? You know, not flimsy or sagging loosely around. And how many times do you think the cruise control was the culprit for setting it off? The cruise is on an arm, right? Let me know.

Hey meanwhile, why don''t you take a test light and have someone hold it on the wiper motor plug while you get inside the car and try different things to set off the wipers. Make sure the test light is grounded good and wiggle the column arms, singal, hazard, brake, engine on, engine off, etc. See what happens.

Everything seems snug and in place on both arms. As far as cruise control, its on the steering wheel, and Ive driven both with and without it and have had it happen. I cant remember whether its happened more or less with cruise, but I think its safe to say its about an even split.
Ill look into it more with a test light and get back to ya.

I started having a problem with the car shutting off while driving and decided it was serious enough that i should take it to a shop. On my way to the shop, it died and i couldnt get it to start back up. I was only a block away from the place too, lol.
So the problem ended up being that the fuse panel under the dash had a couple of fried relays, and the entire fuse panel needed replacement because it had been melted around the contacts for the relays. Being that I only had the car for a couple of days when all the problems started, I decided it was probably something one of the previous owners did, and the problems got worse over time on their own.
It was a $300 fix but i dont have the weird problems anymore.

Edited by: wolfbiker99