Rear wiper, unstoppable

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odysseus

Active Member
Posts
231
Location
Cambridgeshire
Another day, another item on my P38 snagging list.

This one concerns the rear wiper...

The previous owner had disconnected it as it wouldn't stop running. I found this out for myself when I reconnected the motor, operated the motor using the appropriate stalk, watched it wipe the rear screen, then was unable to turn it off. It simply kept running. I eventually pulled the connector to stop it.

What could this be? Is it likely to be my stalk or is it more likely to be the motor? Has anyone seen this before? Any idea as to the fix?
 
Rear wiper should only ever work on intermittent mode it should not run continuously. Have you tried pushing the stalk forwards to switch it off?
 
2.0_hippo said:
possible BECM problem ?
Click to expand...

This presumably is the worst case scenario...

I guess the way to test this would be to replace the motor with a known good one and see if the problem recurrs?

It's worth mentioning that (as far as I can figure out), everything else seems to work ok, so if it is a BeCM problem, it's extremely localised.
 
odysseus said:
Another day, another item on my P38 snagging list.

This one concerns the rear wiper...

The previous owner had disconnected it as it wouldn't stop running. I found this out for myself when I reconnected the motor, operated the motor using the appropriate stalk, watched it wipe the rear screen, then was unable to turn it off. It simply kept running. I eventually pulled the connector to stop it.

What could this be? Is it likely to be my stalk or is it more likely to be the motor? Has anyone seen this before? Any idea as to the fix?
Click to expand...

Sorry didn't realise you wanted to fix
 
Yes, it will stop the rear wiper... However I already have a solution for stopping the rear wiper.

All things being equal though, I'd like to fix the wiper - hence the post. :)
 
Looking at the schematic....the park switch indicates NOT parked when the Orange/Purple wire is Grounded....

To tell the BeCM it has cycled and parked, the O/P wire is then not grounded...trouble is only way to test this would be to snip this wire to emulate the park switch has gone Open Circuit....
 
Saint, your knowledge astounds me and your name is accurate!

This cable of which you speak... Where is it? If it's something at the wiper end of the equation I'm comfortable snipping it. If on the other hand it's a seat off BeCM job, my enthusiasm wanes to say the least!
 
Can be found at the connector on the motor....

Should be 3 wires to it, Orange/Black (Motor Power), Black (Earth) and Orange/Purple (Park Switch)...

No need to get to the BeCM....

It is only a hunch, but as I said, if the BeCM isn't getting the park signal, it won't shut the power to the motor off...only my opinion mind...wire cutting is your discretion!
 
Could very well be a BECM problem.
Typical telltale signs are malfunction of the rear wiper and false bulb failure messages for the indicators....Not necessarily together, you could have only one of these problems.
 
Ok, thanks for that alarming nugget of information Irishrover!

In 10 days of ownership I have seen an erroneous bulb failure message once, and the aforementioned rear wiper issue. That's all though and everything else runs nicely.

If a 'faulty' BECM is behind these issues then frankly I could live with it, however given I understood the BECM is the brain within the P38, I'd expect a faulty one to be throwing up errors all over the shop, which isn't the case thus far.

Given Saint's comments above, I assume it's worth trying the wire snip/new motor test before looking to swap out the BECM?
 
odysseus said:
Ok, thanks for that alarming nugget of information Irishrover!

In 10 days of ownership I have seen an erroneous bulb failure message once, and the aforementioned rear wiper issue. That's all though and everything else runs nicely.

If a 'faulty' BECM is behind these issues then frankly I could live with it, however given I understood the BECM is the brain within the P38, I'd expect a faulty one to be throwing up errors all over the shop, which isn't the case thus far.

Given Saint's comments above, I assume it's worth trying the wire snip/new motor test before looking to swap out the BECM?
Click to expand...
Moisture ingress is a common cause of BECM problems. Check the carpet is not wet in the drivers footwell.
 
Is there a switch somewhere for reverse gear??
When I select reverse gear in my dse my rear wiper operates to clear window..
Could it be that at fault thinking its still in reverse??
Just a thought,or perhaps mine isn't supposed to do that :)
 
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