2000 V70R headlight wiper motors check and repair

[scot850]

Hi folks,

Decided to start a new thread as 2 of the 3 items on the old one have been answered sufficiently that I can (or have fixed the issue) thanks to the excellent guidance and help.

The one issue I need more help with is the diagnostics of 2 used headlight wiper units I picked up to add to my spares stash as the price was good from our local Pick-n-Pull. If they are faulty I have the option to return them for a refund, but again in my focus of continued Volvo learning, I'd like more info on testing and repairing these units if possible.

I stated in my previous thread that I tested the units by connecting them both (one at a time!) to the LH unit wiring connection of my 2000 V70R. Both units would run perhaps one or 2 sweeps and then stop. I had the units laying on their backs with a piece of tape stuck to the shafts to see movement (no help available!!).

If I tried to get the units to work a 2nd time there was nothing. Does it matter if I tested a RH unit on the LF side? Wouldn't think so.

To get the units to work again, I had to switch the ignition OFF and then ON again, and I could see what looked like the units re-setting their positions, but they would not run again if re-tried. Is this not the correct way to test these units? Do they need the wiper arms and resistance to work correctly to allow the arms to reach the ends of their sweeps to continue to run?

Refitting the connection to the existing unit on the car an all is well with it.

Jimmy 57 says that there is a resistor that (if I rad into his info correctly) acts like a fuse in case the wiper is frozen to the headlight. But what is the point of this if it then renders the unit useless if it burns out? Is it not meant to burn out, but somehow prevent the unit overloading and stop it running?

If it fails, jimmy57 says you can replace/by-pass the resistor with copper wire or aluminum foil, but it removes the safety feature, and that the resistor can fail with age.

If this is the case (and I'm assuming the resistor is in the unit at this point) then, what is the best way to open the unit without breaking the barb tabs? Last time I tried this, it ended in a massacre of broken tabs. Assuming the resistor is internal to the unit, what prevents replacing the resistor? Is it a hard to find part, or difficult to install?

If I can get enough info, I would be happy to tackle a full repair of a unit for our database for the future. Hopefully there is one of you out there that can help.

Many thanks,

Neil.

[scot850]

Found this reference to someone who repaired a similar headlight wiper motor on a SAAB 9000.

Didn't see a reference to the resistor jimmy57 mentioned in this motor. Possibly it is different, although visually similar.

http://www.saab9000.com/procedures/elec ... repair.php

Neil.

[cn90]

Don't know if this helps but read it just in case...

http://blog.fcpeuro.com/2014/04/03/how- ... per-motor/

[scot850]

Thanks cn90!

I also found another repair document on the repair of headlight motors and link is below. Lots of pictures. Those SAAB guys have done a good job.

http://pages.infinit.net/mlbriand/saab/ ... wiper.html

Neil.