I have a 98 S70 that has a headlight wiper out of sync. Whenever I turn on a cleaning cycle, the driver side headlight wiper parks in the vertical position.

However, after I shut the vehicle off and restart it, this wiper returns to the proper parked position.

Any ideas what is wrong?

The motor has a position sensor in it and power is cut to the motor when the wipers are turned off after a wash. Try washing and see if both headlight wipers are going in synch. If the driver's side is slow to start, then it could be a weak motor which gets parked during system startup checking.
It could be a poor ground or like Dick's. Fortunately, it is the easier of the 2 motors to replace/repair.

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

The arm may just be loose. Lift up the plastic cover and try tightening it a little. A 10mm, I think.

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

Had the same problem on my 98 and finally gave up and got a good used one. Hope it is just the nut as Klaus suggested.

dick

Klaus

Checked the arm, it is tight.

What's interesting is that a restart of the vehicle parks the wiper in the proper parked position. I think it might be something in the wiper motor assembly.

Same symptom mine had. Am sure there is something in the motor that is out of wack, but I was not in an experimental mode and just replaced it.

dick

I've checked all the obvious and it all points to something not right inside the motor.

Anyone know how much one of these headlight wiper motor assemblies sells for? I'll probably replace the unit when the weather warms up and disassemble the failed unit to see if it can be repaired for a spare.

Ditto, get a used one for the proper side. They are not interchangeable from sid to side. East coast -- try Erie vovo on their 800 number.
The driver's side is relatively easy to replace, the passenger side is impossible.

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

You can check on fcpgroton or go for a good used one. I did the latter and have been happy.

dick