Window wiper problemo... can you help?

skunkwerx

Weird one here. 

Its a 2010 Renault Megane and only my rear wiper is affected. 

It still works, but if I turn it on it will consantly wipe for about 10 seconds then just stop anywhere it pleases.

Isually if I hold the button to mist the rear window with wiper fluid, it wipes once, pauses then wipes again and returns to its stationary position. 

However even doing that it just wipes constantly for around 10 secs then stops where it pleases.

Once its stopped wherever it likes, its non responsive for like a minute or two no matter what buttons I press. But eventually it will work again but just repeat the same problem. 

I’m no mechanic but I presume as the wiper does actually wipe, that the motor, fuse and the switches are not the problem. Do wipers have a module that could be at fault?

My previous focus had an instance where water got in the bulkhead in the engine bay and damaged a gem module which resulted in no front wiper function once.
Ford wanted £500 odd for that..

So is there anything I can try at home first?

cheers all!

ICBM

I wonder if the microswitch that tells it when it's back at the rest position is faulty? I'm fairly sure that goes 'open' when the wiper is at rest so it prevents the cycle starting again. If it's not making good contact when it's supposed to be 'closed', the wiper will just stop anywhere.

Or at least, that's how old-fashioned mechanical/relay ones work - but I don't know if the modern ones do. If it is the cause, the switch will be on the wiper motor body somewhere.

Bridgehouse

My guess is worn wires in the rubber gaitor going to the tailgate.

Open the boot and pop back the rubber gaitor going from the LHS body to the tailgate and inspect the wires. They have a habit of self destructing in the Megane and it’s possible they are shorting out. If they are you can wrap them and reinsulate them.

If not, then the motor could be foobarred - it has an onboard electronic relay iirc so not an easy job just to swap that bit out. You could probably get a whole assembly for about £50 tho...

skunkwerx

Cheers fellas. 

I’ll crack it open tomorrow to see what I can see. 

What you’ve mentioned doing is within my realms of ‘doable’.. I have some sockets and screwdrivers, leccy tape etc but not much else. Anything deeper than pulling trims off and undoing bolts is usually a recipe for disaster haha! 

If it comes to it, its just the rear so its not a legal/mot problem is it? Or would it need to work if its on? Could just de-wiper the arm and bung the hole though if it comes to it... 

Needs a decent service and brake fluid change which is where the moneys gotta go first haha... ahh cars. 

ICBM

skunkwerx said:

If it comes to it, its just the rear so its not a legal/mot problem is it? Or would it need to work if its on? Could just de-wiper the arm and bung the hole though if it comes to it...

A long time ago I had a car with a dead rear wiper motor - while I was waiting to get a replacement from a scrapyard it needed to be MOT'd.

The answer was: if the wiper is fitted it must work, but having one is not a legal requirement, so you can remove it - I did, put a bit of tape over the hole and it passed. That was twenty years ago though, the rules may have changed...