99 s70 headlight wiper motor problems?

[nyurch]

My headlight wipers have a mind of their own. Sometimes they work, sometimes they don't. Sometimes they are stuck in all positions (for days) and sometimes the go down by themselves at each start of the engine. I know the wiper motor is right behind the headlight it's self (correct?) and I live close to a junk yard so I'm sure two motors won't be hard to find.. (what years will work? there are tons of 850s there.. ) You cannot move the wipers back down (I didn't try alot of force). I was wondering if this sounds like a fix? or should I just flat out replace the motors? Thank you

[jblackburn]

If you can find working ones, any from an 850 will do. Most are probably broken, too, though.

[jimmy57]

These motors are easily repaired except for the part of removing it and replacing it. If it runs all the time and won't park this IS NOT the fix. If the wiper arm stops wherever it pleases and will be parked later usually THIS IS IT!
The motor has stall protection built in. IF the wiper arm froze to headlamp or got caught under the stops they don't want it burning up so they put a PTC resistor disc inside. The disc is 2-3 ohms but when it gets hot from overload it goes to several hundred ohms and effectively cuts off current to motor. The problem is the disc can slide out of place and it also gets corroded.
You have to pry the cover off motor back and some of the tabs will likely break but the motor can be assembled with silicone sealer and clamped until it dries.

Open motor.
Look next to the the silver motor and you will see copper strips with a 10 mm square wafer between them. Gently pull the wafer out and sand it on both sides gently and then put some high temp grease on it and push it down between the copper strips. Put cover back on motor so the drive arm and the park switch will be held in correct position and drive arm will not pop off. Ground the black wire, apply power to the wire on other end (I think red) and the motor should run indefinitely. Remove power from the end wire and touch it to the middle wire (yellow I think) and the motor should rotate and then stop when it is in park position. If you by chance cut it off and it was in park then it won't do anything when you apply power to that wire, touch other wire briefly and repeat the park test.
Once it is happily working then press it back together until tabs are latched. If tabs broke then apply silicone sealer and clamp together for the silicone to cure. GO easy on the silicone so it doesn't get in motor and glue moving parts together.

[scot850]

Added this link to the thread as may be useful. Found it on a Saab website as a replacement thermal resistor/fuse for the square metal one that fails in the headlight wipers.

http://forums.swedespeed.com/showthread ... -wiper-fix

Recommendation is to go for the 4.0A over the 3.0A (so RGE400-ND from Littlefuse) from Digikey.

Neil.