O/T Wiper Motor trouble

[Curious Orange]

Just a quick question for the petrol-heads out there.

The rear wiper on my Golf stopped working.

I think it may be a combination of an electrical problem somewhere and a rather stiff spindle. But it would be rather useful to know what voltage the motor should be receiving in order to actuate, as the 1 or 2 volts my multimeter was registering seems a little on the low side to me?

 

[Titanic]

Almost as irritating as the rear wiper on my Passat, which today decided it wouldn't switch off !

Any advice gratefully received.

 

[Curious Orange]

Almost as irritating as the rear wiper on my Passat, which today decided it wouldn't switch off !

Any advice gratefully received.

Sounds like you may have a duff relay, which isn't the problem with mine as I replaced it and it made no difference.

 

[Titanic]

Is that an easy job ? were do I find it and how do I tell if it's duff ??

 

[Curious Orange]

Is that an easy job ? were do I find it and how do I tell if it's duff ??

Changing a relay is easy, as they push fit into the same box that contains the fuses - on my car this is located under the dash on the drivers side. The wiper working randomly could indicate a dodgy relay (not guaranteed btw), but if yours just won't turn off then it could also be a dodgy switch on the wiper stalk on your steering column (a much more fiddly job).

At least your wiper works. Think I'll pop into the scrap yard near Pease Pottage before the first home match and get some spares.


I could still do with knowing the voltage the motor should be working at btw, I assume it should be getting the full 12v, but some confirmation would be nice.

 

[chip]

Its going to be ~12V.

How is the power delivered to the motor? Are there brass contacts on the hatchback door that make the circuit? If there are, these often corrode or become oxidized and you should give them a clean with wire wool, emery cloth or a fine grade of "wet & dry" and then cover them with vaseline or something similar. Occasionally, they are spring loaded and these can just fail.

If there is a wiring harness that attaches around the door hinges, check that the wiring has not become frayed.

The low voltage could be due to a damaged wire at some obscure place in the loom. Is the supply that the relay switches at 12V at the relay terminals? It is unlikely to just be a fuse as you would then get 0V dc so you would have to check all the way back from the motor to the supply before the relay.

Is the 12V with or without the motor connected and are you measuring accross the supply terminals on the motor? Essentially, I a asking if you can isolate the low voltage before or after the relay as that will identify the part of the loom that has failed. Has the wiper been intermitent? That would help identify the type of fault.

 

[Curious Orange]

The low voltage was measured across the connector in the boot (on the power side), with the motor disconnected.

I have wired the motor up to an alternative 12v power supply and it does run.

The wiper spindle is quite stiff (I'll either try and clean this up again or replace it from the scrapyard), so I'll re-check whether the motor runs whilst connected to the loom, but not the wiper linkage. Then work back to the fuse-box I guess.