2002 Mercury Mountaineer • 125,000 miles

I have an odd question. I have a 2002 Mercury Mountaineer, runs great. But lately, my windshield wipers have been acting up. When I first start the car, they don't work. However, after the car has been running about 10 minutes, they work, but only at a couple different speeds. Once I stop the engine for a while, then restart it, the same problem with the wipers. Is this a simple fuse or does this have something bigger attached? Everything else electrical in the car works fine, only the wipers. Any ideas? Could this be the cpu? Or epu? (Sorry, I forget what you guys call it, the brain of the car's computer). If it was that, wouldn't other systems on the car be starting to fail? Please help.
December 20, 2012.

There are 2 things that could be happening. There is a wiper control board for the intermin=tant function which may be failing. If you find you later have trouble with the high or low speeds that are not intermitant then the multi function switch is bad.

That is what's happening already. When the wipers come on, they are only on a regular speed. Intermittant fast or slow no longer work. Ford dealership service rep, who I'm assuming was trying to upsale, said it's most likely the cpu/epu (computer brain) is going bad and I should replace that. It's a $850 part! He never mentioned the wiper control. Is there a way I could check that out? How much to fix something like that? Could the Ford Dealership be correct? But if the cpu/epu was going bad, wouldn't other systems in my car be failing as well?

Dec 20, 2012.
The wiper control board is almost always a seperate PCU unit seperate from the ECU. I am attaching the wiring diagram that shows the control board is a solid state unit that is part of the wiper motor. If you will notice the multi-function switch has intervals for different intermitant speeds. They all lead to the solid state controller board. The high and low speed are simply controlled by relays in the wiper motors as they are a constant on function. So, the ECU is not involved. You need to get a NEW WIPER MOTOR WHICH WILL HAVE A NEW CONTROL BOARD IN IT. I WOULD LOOK FOR A RE-MAN. YOU SHOULD TRY WWW. ROCKAUTO. COM AS THEY HAVE THE BEST PRICES AND NAME BRANDS ON RE-MANED AND EVEN NEW PARTS.

Thank you so much!

Dec 21, 2012.
Your very welcome. I hope it all works out. Come back anytime you need anything.