Wiper motor low speed not working

[hands_aus]

Wiper motor low speed not working
As part of my diagnosis I took the plug off and applied earth and applied 12V to each of the other terminals one at a time.
#4 parked the motor
#1 high speed worked
#3 low speed no movement, noise

I am going to remove the motor from the car to inspect, clean and possibly have it rewound.
Can someone tell me if the small bracket? on the wiper motor drive shaft is held on by a spline and if yes how to remove it.

I think this is the correct approach rather than mess around with the linkage bracket.
thanks, all info welcome

[hands_aus]

Obviously this was in the wrong section

I ended up removing the wiper motor and then used two opposing screwdrivers to remove the small drive bracket.

On the wiper motor bench test the low speed did not work.

It is a simple job to remove the screws and end plate from the motor which allowed me to remove the cogs one at a time and wipe the excess grease from them.
After bench testing the wiper motor again, I found it worked on both speeds.

I applied some new grease to the cogs and re-assembled the motor.
After reflecting on the age and amount of use the wiper motor would have had, I decided the brushes should be like new, so I left them alone.

When I further bench tested the re-assembled motor both speed worked.

Next I checked the voltages at the relay plug top I found everything was as it should be.

That eliminated the cables and plug top and the steering column switch as a source of problems.

I had a good look at the wiper relay and after bench testing it with 12V I found that terminals 56 and 56a were open circuit when they should have been closed.

I took the cover off the relay (fairly easy process) and found the relay contacts were completely covered in black carbon which prevented 12V to flow.

Fine wet and dry paper cleaned the contacts like new.

Pre-assembly bench testing showed everything was back to normal when switched from the steering column switch.

I re-assembled the relay and mounted it and the motor and arm connections under the dash.

As a bonus to my car I gave it new wiper blades.

Total cost $8.86

[georgem]

Hey Bob,

Those hands of yours are very useful...................

[hands_aus]

Hey George,

They sure are, but sometimes when I am trying to work behind the dash board they seem enormous.
I came to the conclusion that MB sort out people with small hands for working in there.


cheers