Rear wiper stopped working:

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v8twins

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73
Rear wiper stopped working P38A:
One for you, someone must have come across this before?


Rear wiper stopped working the week before last, it actually stopped half way through a sweep (was pointing halfway down the rear window) during the MOT!


When you listened you could hear the motor trying to work, but the arm did not move, so I removed the motor and gear assembly, stripped it down, cleaned it all up, lubricated where required, resembled then hung it on the wiring loom and it worked fine. Bolted it back in the car and it stopped working, however the motor looked iffy as one of the bushes had marked the commutator, so was not surprised really. :confused:


Purchased a pre-used unit off eBay (has a 90 day warranty, allegedly tested before being shipped) and that does not work either when connected to the wiring harness, so currently assuming a wiring problem!

Checked fuse 16, which is good.

Checked for power on the three wires in the connector, have the following results:
One has a live {+12V} condition, Colour red [could be orange] with blue strip, the one coloured Red with Black stripe has an earth condition and the other coloured all Black also has an earth condition, this condition happens as soon as the ignition is turned on and all three they stay in that condition irrespective of whether the rear wiper switch is turned on or not.

Any thoughts?

Cheers Steve
 
Hi Datatek, the version of RAVE I have is so old that it does not have wiring diagrams in it, it does have circuits but they do not show the wire colours or expected conditions in any state, where can I get a later version please?
Steve
 
Hi Datatek, the version of RAVE I have is so old that it does not have wiring diagrams in it, it does have circuits but they do not show the wire colours or expected conditions in any state, where can I get a later version please?
Steve
Look in the "How To" section for a post by Wammers on the EAS, it will have a link to a download.
 
Datatek, found the ZIP file thank you.
Wammers, fuse good, need to check the relay in daylight, thanks.
Steve
 
Datatek, found the ZIP file thank you.
Wammers, fuse good, need to check the relay in daylight, thanks.
Steve

Relay is inside BECM. Not visible. Unless you strip it down of course. Not a good idea though. Think i would be assuming duff motor and duff Ebay motor may just need cleaning.
 
Last edited:
Hi all, quick update, wiring sounds to be good, same conditions seen on wiring wiper switch on or off, need to disconnect at BeCM and check there is same then relay knackered, if not then wiring suspect! Currently my money is on the BeCM. With ignition on Red with Blue wire always hot (agrees with RAVE) Red with Black wire earth supposed to turn hot when wiper turned on (according RAVE) mines stays earth, Black stays earth (agrees with RAVE), its the relay in BeCM that turns Red with Black wire from earth to hot apparently so I have been told to make the wiper work. That is not happening, on the harness end, so need to check on the BeCM, but if its the same! Don't know yet but suspect it will be.....

Steve
 
Hi all, quick update, wiring sounds to be good, same conditions seen on wiring wiper switch on or off, need to disconnect at BeCM and check there is same then relay knackered, if not then wiring suspect! Currently my money is on the BeCM. With ignition on Red with Blue wire always hot (agrees with RAVE) Red with Black wire earth supposed to turn hot when wiper turned on (according RAVE) mines stays earth, Black stays earth (agrees with RAVE), its the relay in BeCM that turns Red with Black wire from earth to hot apparently so I have been told to make the wiper work. That is not happening, on the harness end, so need to check on the BeCM, but if its the same! Don't know yet but suspect it will be.....

Steve
Could still be a broken wire, It will not change state if there is a break.
 
Would check the outputs on the relevant cables at the BECM before i started stripping it. If the output is correct that would prove a break then you just have to find it.
 
IT WORKS!
With the battery disconnected, here is what I did:
Removed the connector C1584 from the BeCM (battery disconnected as I had no idea what removing this connecter would do with the car live!)
Removed the connector C0388 from the wiper motor
Tested each wire back to the connector at the motor, all wires good, no breaks and only 0.03 voltage drop over the distance (as expected)
Reconnected the battery
Tested the outputs of the BeCM (connector C1584 still disconnected) on pins 1 and 7, oh pin 7 is not changing from Earth to Positive [to activate the wiper motor] when the multifunction switch on the steering column is set to rear wipe and ignition on, is the BeCM stuffed?
Put the gearbox into reverse, rear wiper off, front wipers on, turned on the ignition and - no change in the state of pin 7. The rear wiper should have operated, its definitely pointing towards the BeCM being the problem, maybe relay 8 is naff; burnt out as a result of the old motor failing!!!
Reconnected everything and tried again in a last vein of hope and nothing worked.
I wonder - don't try this at home just cos I was stupid enough to do it.... Got my rubber mallet and gave the BeCM a sharp [but softie] blow and it all bounced into life, the wiper now works from the switch and when in reverse. Yep the relay was stuck, maybe burnt contacts who knows.
Who knows how long it will keep working but for now it works.
There the story of the now working rear wiper.
Cheers
Steve
 
IT WORKS!
With the battery disconnected, here is what I did:
Removed the connector C1584 from the BeCM (battery disconnected as I had no idea what removing this connecter would do with the car live!)
Removed the connector C0388 from the wiper motor
Tested each wire back to the connector at the motor, all wires good, no breaks and only 0.03 voltage drop over the distance (as expected)
Reconnected the battery
Tested the outputs of the BeCM (connector C1584 still disconnected) on pins 1 and 7, oh pin 7 is not changing from Earth to Positive [to activate the wiper motor] when the multifunction switch on the steering column is set to rear wipe and ignition on, is the BeCM stuffed?
Put the gearbox into reverse, rear wiper off, front wipers on, turned on the ignition and - no change in the state of pin 7. The rear wiper should have operated, its definitely pointing towards the BeCM being the problem, maybe relay 8 is naff; burnt out as a result of the old motor failing!!!
Reconnected everything and tried again in a last vein of hope and nothing worked.
I wonder - don't try this at home just cos I was stupid enough to do it.... Got my rubber mallet and gave the BeCM a sharp [but softie] blow and it all bounced into life, the wiper now works from the switch and when in reverse. Yep the relay was stuck, maybe burnt contacts who knows.
Who knows how long it will keep working but for now it works.
There the story of the now working rear wiper.
Cheers
Steve

A soft blow with a rubber hammer. That has to be the most cost effective BECM repair ever. :D:D:D
 
No not ex-REME, but am ex-GPO engineer and ELP, now that shows my age!

GPO ELP (Electric Light and power) that became BT Telephone engineer with electrical qualifications - same thing I guess as REME, had a big hammer to fix things, except it was rubber less visible damage!
 
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