Touring rear wash/wipe wiring diagram

Fri Apr 15, 2005 8:03 pm

Can anyone help with a diagram please? I've got problems and I need to sort out which wires should have live feed, which ones switched feed etc.
Cheers
Stuart.

Fri Apr 15, 2005 8:45 pm

I don't have a tourer any more but i think the relay for the wiper is in the tailgate.
I assume the problem you have is the wiper stops in the middle of the window or runs off the glass. The problem i had was mechanical not electrical and a good clean up cured it.

Fri Apr 15, 2005 9:01 pm

Hi Martin. The problem that I have is that the wiper has a mind of its own, it works without the switch being pressed.
I've located the relay, and disconnecting it cures the problem. I've also fitted another (second-hand) relay, and the problem's still evident.
I suppose it's possible that the two relays could both have the same fault.
What I want to do is by-pass the relay, but I need to know which wires should be powered and when, and which terminals to bridge to allow the wiper to work directly from the switch. Pulling the switch out of the dash and out of its plug doesn't stop the wiper!! At the moment, I have one wire to the relay that is live (not switched). My first concern is should that cable be live? If, as I suspect, it shouldn't then I have to trace it back and find a reason for it being so.
Cheers
Stuart.

Fri Apr 15, 2005 9:08 pm

Are you sure you have the correct relay? They all look the same but can have different layouts inside.
Is it in the tailgate or the fusebox?

Fri Apr 15, 2005 9:27 pm

Martinaston wrote:Are you sure you have the correct relay?

Yes, I'm sure. It's in the left-hand boot compartment (the one with the tools in), beside the bulb failure control relay.

Sat Apr 16, 2005 12:27 am

Sorry, but I can't make any sense of my own notes and diagrams for the rear wiper, but there has to be a permanent feed for the parking mechanism.
My guess would be that your fault is with this self park mechanism.The parking switch is the black/red and brown wires going to a block on the back of the motor (if I'm making any sense of my notes).
Try disconnecting one of these wires and see if that cures the problem. The wiper will just stop where it is when you switch off, of course, with this done.
I've got a problem with the rear wiper on my M50 touring which is due to be MOT'd, taxed and insured shortly, so I will be sorting my notes soon when I can find the time.

Sat Apr 16, 2005 12:57 am

I think you might have misunderstood when i said the right relay i meant the correct unit, if you look in the fusebox you will find two or three relays that look the same but operate in diferent ways.
If it's terminals are numbered 30,85,86,87. Terminal 30 should be constant power if any others have power your wiring's shagged.
Check for water around that area as the back light's leak and the water bottle is in there as well.
If thats not the problem then as i first surgested clean the motor gears because if there is too much gunk covering the magnet inside the reed switch no longer breaks the circuit to park the wiper.

Sat Apr 16, 2005 7:14 am

Thanks for the help and advice Chaps. I'll be able to have a better look at it over the weekend.

Sat Apr 16, 2005 10:55 am

Stuart, have you disconnected all the wires (even the one on the washer bottle pump) and checked it out ?

I had a strange problem on my touring, where the wiper would work, but no spray.

So I disconnected it all and cleaned everything up, and found the rear washer bottle immersed in a puddle, so obviously, there would be problems.

I just cleaned and dried it all up and left it to air (in my garage) for a few days, then started connecting bits up.

Everything worked apart from the wash/wipe.

My neighbour (who is a mechanic himself) came around and we used a voltmeter and tester to check the voltage and see what's going on.

Somewhere along the line, we suspect, the wiring didn't have the the correct voltage (earth I think) feed. So he tried swapping the Positive and Negative wires and tested the connections for the relay one by one.

But strangely, it just decided to work after we swapped the big relay in the fusebox for the front wipers.

Don't ask me how, but that cured the problem. Does not make sense to me still

Sat Apr 16, 2005 12:31 pm

Cheers Bharat, that's given me a bit more to go on.

Sat Apr 16, 2005 1:48 pm

The rear washer pump has a 12V+ feed, purple/red and is operated by earthing the other wire, brown/black. This wire has a branch to pin 95 of the control module, and runs all the way back to pin 8 of the washer section of the switch. A black/purple wire then goes from pin 6 of the switch all the way back to the rear wiper motor where it is finally earthed by a contact inside the wiper gearbox, which limits washer operation to one direction of the wipers arc.
The usual problem is that the O ring feeding the washer water up the wiper spindle fails, leaks water into the gearbox, and corrodes the metal plate that connects with the sliding contact.
Easiest fix is to permanently earth the black/purple wire. Only downside is that you will use twice as much rear washer water.

Sun Apr 17, 2005 12:15 am

Right, inspired by this thread, I've had a go at sorting out my M50's rear wash / wipe this afternoon.
Problem with the wiper was it parked ar random. Took out the motor, and someone has completely removed the wires to the park microswitch in the rear cover. Opened it up and checked out the microswitch which has turned out to be permanently open circuit.
I would think that the original problem with this motor was the same as Essbee's, and the bodged cure was as I've said above.
Found a similar microswitch on the front electric windows of the E34 that donated it's engine to my touring. The roller lever arm transferred over OK, but the main difference was, that where there were two mounting holes through the original switch, the replacement had two plastic rods sticking out, similar to the mounts for the switch in the gearbox.
Cut the two mounts in the gearbox off, and drilled appropriately sized holes in exactly the same place. Pushed switch into place and heat riveted the ends of the rods with a soldering iron outside to keep it in place.
Looks like it should work OK, but not replaced into car and tried yet.

Sun Apr 17, 2005 12:18 am

Forgot to add, that as a result of the above, I have now sorted my notes, have a complete wiring diagram for the rear wash/wipe and have sorted how it all works.

Mon Apr 18, 2005 1:42 pm

I got a miracle cure to mine by sitting with both buttons pushed for a bit with the ignition on. I'm not sure it its permanent though

I think it worked by cleaning the contacts that Brian refered to

Sun Mar 05, 2006 9:33 pm

Brianmoooore wrote:Forgot to add, that as a result of the above, I have now sorted my notes, have a complete wiring diagram for the rear wash/wipe and have sorted how it all works.

Hi Brian,
would you mind sharing this info with me ?
At this moment i got similar problems ...

Thanks.

Thu Aug 02, 2007 10:33 pm

Which relays operate the front / rear wash?

My rear wash has packed up, wiper still works fine, but no wash, the switch doesn't even light up when I push it.

Thanks

Thu Aug 02, 2007 11:00 pm

FlashBastd wrote:Which relays operate the front / rear wash?

My rear wash has packed up, wiper still works fine, but no wash, the switch doesn't even light up when I push it.

Thanks

No relays involved in the front normal screen wash - the pump works directly from the switch.
No relays involved in the rear washer either. Pump is switched directly by the switch and a wiping contact in the rear wiper motor. Try earthing the black/purple wire at the switch and see if this brings the washer to life.

Love seeing some of these old posts! I've no recollection at all of repairing the parking arrangements of the rear wiper on my M50!

Thu Aug 02, 2007 11:05 pm

I have now discovered that I can hear a clicking from the rear when I hit the wash button, and if I hold it down, the wiper goes. My plan is to swap the pumps, and see if that makes any difference. Sound logical? Getting the switch out to check the black/purple wire is a bit awkward as I will have to remove the stereo and cage to pop it out.