Chattering Wind Screen wiper

[MetBlue]

For a while now, I've had a chattering sound from behind the clocks when using the wipers. It's not dependant on mode of operation, happening in Single, continuous or intermittent mode. It doesn't occur on every sweep, but most, and seems to only happen in the last half of the return sweep !
It sounds like a relay hunting. AFAIK, the only relay is in the Pektron Wiper control module so out it came.
After a little patient safe breaking, I'm inside it without terminal damage to the case


I guess I was hoping to find a dry solder joint, or worse case, maybe a fried component, but all looks generally good. Maybe a little browning of the relay contacts, but not too bad. Anyway, have cleaned contact faces with fine emery cloth, just in case it makes any difference.

Next step will be to remove, re-grease and fit new brush plate to the motor.
Will post an update when rebuilt on whether problem solved. I might even try just plugging the module back in before doing the motor, just to see if the dirty contacts look like they were the route cause.

Tony

[Lotus-e-Clan]

Not suggesting this your problem, but others who may look at the thread title might have chattering blades that a simple corrective-twist of the wiper ARM can solve.

The wiper blade rubber needs to be set absolutely perpendicular to the windscreen at rest, such that as the arm changes direction the rubber can flip over each way and act like a squeegie in BOTH directions. If the rubber blade is angled in one direction at rest it will only work as a squeegie in ONE drection, and chatter on the return.

Rubber chatter creates more resistance and can strain the mechanism/motor too (during the sweep that chatters).

Here is an old youtube demo of the fix.
https://www.youtube.com/watch?v=PHTjwpC44zo
Recommended because it worked for me anyhow!

[MetBlue]

Peter : Your comment about the extra load on the motor might well explain why it always happens on the last half of the return sweep.
The sound I get definitely has electrical origins not mechanical, but it may be that the wiper motor is working harder as it approaches park position in my case.

Tony

[MetBlue]

I'm now pretty certain the cause of this relay chatter was an almost seized wiper spindle. The motor must have been working very hard to drive the wiper.
During diagnosis, I found no obvious problems with the delay module, and the motor was in good order with virtually new brushes.
On removal of the wiper spindle though, it was VERY rust ( had been the source of a major water leak a year or so back, but clearly had been leaking for years) and the outer casing a fraction of its original size due to corrosion. Once in the vice, turned a full 180 degrees in the hope maybe I could free things up and it seized solid.
All rebuilt with a new spindle, and all seems good now.
Tony