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99 s70 headlight wiper motor problems?

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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nyurch
Posts: 83
Joined: Tue Dec 15, 2009 4:00 pm
Year and Model: '98 S70GLT '02V70X/C
Location: Eastern PA

99 s70 headlight wiper motor problems?

Post by 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
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Year and Model: 1998 S70 T5
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Re: 99 s70 headlight wiper motor problems?

Post by jblackburn »

If you can find working ones, any from an 850 will do. Most are probably broken, too, though.
'98 S70 T5
2016 Chevy Cruze Premier


A learning experience is one of those things that says, "You know that thing you just did? Don't do that."

mercuic: Long live the tractor motor!
jimmy57
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Re: 99 s70 headlight wiper motor problems?

Post by 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
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Re: 99 S70 headlight wiper motor problems?

Post by 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.
2000 V70 R - still being an endless PITA
2006 XC70
2003 Toyota 4Runner V8 Limited
2015 Kia Sportage EX-L
1993 850 GLT -Sold
1998 V70 XC - Sold
1997 Volvo 850 SE NA - Went to niece in California - Sold
2000 V70 SE NA - New project and test bed - Sold
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