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105 Rear wiper -- Haunted !!!

wallabybob

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australia
Thread shifted from 105FSM
Probably not the right place to discuss this Rob - but here goes anyway.
The rear wiper does not work at all until either one of the rear doors or the tailgate
are opened - then it all works fine (even the delayed wipe) but as soon as the door is closed
the wiper loses its 12v feed and stops after self parking - it's looking more and more like
an Instrumentation ECU fault dammit !!!

Pop a new thread up under the 105 section Bob, you’ll get more responses especially if you title it ‘Rear wiper only works with door open’. Have you checked the loom as above, it will almost certainly be where there is a break in the wire.

Rob, I think you are missing the point here, the wiper works fine if either of the rear passenger doors or the tailgate are opened - I can simulate the fault by operating the latch in the tailgate with the door in the open position - that rules out the wiring in the tail gate because it works (and doesn't work depending on the latch condition) There is 12 volts present to run the wipers until all 3 door are closed then it disappears. From the schematic in the FSM (and thanks for that) the courtesy light switches are commoned and send a signal to the
instrumentation ECU to switch on the courtesy lights and the open door indicator light on the dash. The 12 volts for the wiper motor is switched on and off by this ECU but in this case the operation is opposite to expectation.. I will attack the ECU when I get a chance and see what I can come up with. There was a similar thread (exactly the same symptoms) on the LCOOL forum some time ago but I cannot find it now so whether it was resolved or not - I know not!
Regards Greg
 
Not got a 105 so know nothing about them, all I can suggest is anything that's run by an ECU is a pain in the arse.
Before you go mad and rip everything apart do a battery disconnect for 10min, it may just be the ECU has thrown pissy fit, like a home pc, throws a pissy and nobody knows why, reboot it and it all starts working again..... good luck.
 
Greg, apologies, yes clearly I have missed the point as I was thinking 80 rather than 105 based on @clivehorridge ‘s experience where he had the loom to the ambulance doors break and catch fire. :scared-eek::angry-extinguishfl:I’ve also seen this on dishwashers etc.

I’m not sure your problem is in the ECU itself but of course could be. Simplest thing would be to find a pal with the same or similar vehicle and swap the Body ECU (I presume it’s the Body ECU) temporarily and see if the fault goes with it. Of course you may find your ECU has water damage in which case it could be the smoking gun. First find a willing 105 owner.

One thing you could look at if you’ve owned the truck for a while before this started to happen is to think of what changed around the time this problem started. Tow bar fitted perhaps, bulbs changed for LEDs, interior light damaged, anything that might give a clue.
 
Rob, it is a 2001 105 and has the early style electrics -- the wiper is run via the instrument ECU which sits in behind the radio. I have only had the 105 for a few months and inherited this fault with it. It has never been offroad, always been a kids taxi and a caravan tug - here is no sign of any water damage or indeed any other damage.
White90, I have had the batteries disconnected for longer than an hour on a couple of occasions but the fault persists so I really think it's time to pull the ECU out for an inspection. I am a bit stuck for time at the moment and it could be a couple of weeks before I get to it but I will update when I find something.
I asked the question initially in the hope that someone had been plagued with the same fault and had an easy fix !!
Greg
 
Hi Rob, I recently had a very similar issue with my 105 with Barn Doors. Although my symptoms were a little different it's now fixed after I found multiple issues which required 1. wiring repair and 2. Replacing the body control module (BCM) behind the radio. Can I suggest that you firstly re-check the wiring at the rear of the vehicle in particular where the wiring leaves the body to the rear doors, this area is under stress due to flexing so the fault may be very well intermittent due to a broken wire closing the circuit when your door is open (wipers working) and creating an open circuit when the door is closed (wipers not working). The next step is to try a donor BCM as previously suggested. I hope this helps.
 
Most problems withe rear wiper has been caused by moisture in the harness plug in the bottom left corner of the rear hatch.
Another common problem comes after changing the radio, or other work in that area. A plug to the ECU (partly) disconnected, or a wire cut or earthed.
Then, third most common, is where the cable flexes between the hatch and body. Either rubbing against earth, or broken.
I can't positively connect any of these 3 with the funny symptoms, but a dislocated ecu plug, or moisture in the plug at the back, can certainly trick the ecu into doing strange things.
 
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Hi Rob, I recently had a very similar issue with my 105 with Barn Doors. Although my symptoms were a little different it's now fixed after I found multiple issues which required 1. wiring repair and 2. Replacing the body control module (BCM) behind the radio. Can I suggest that you firstly re-check the wiring at the rear of the vehicle in particular where the wiring leaves the body to the rear doors, this area is under stress due to flexing so the fault may be very well intermittent due to a broken wire closing the circuit when your door is open (wipers working) and creating an open circuit when the door is closed (wipers not working). The next step is to try a donor BCM as previously suggested. I hope this helps.

As mentioned above, my truck has ambulance (barn) type doors (and I appreciate the OP has a tailgate, but my problem started with the rear wipers coming on by themselves.

Then the rear right quarter wiring caught fire.

Long story short, there were broken wires where they go to the doors, joining hands and causing shorts....

All fixed now bar the legacy of overheated wires all through the truck :whistle:
 
Hi Rob, I recently had a very similar issue with my 105 with Barn Doors. Although my symptoms were a little different it's now fixed after I found multiple issues which required 1. wiring repair and 2. Replacing the body control module (BCM) behind the radio. Can I suggest that you firstly re-check the wiring at the rear of the vehicle in particular where the wiring leaves the body to the rear doors, this area is under stress due to flexing so the fault may be very well intermittent due to a broken wire closing the circuit when your door is open (wipers working) and creating an open circuit when the door is closed (wipers not working). The next step is to try a donor BCM as previously suggested. I hope this helps.

Stan, With the door (hatch) in the open position I can make the wiper work /not work by operating the lock with a screwdriver. Either of the back passenger doors cause the fault to come and go depending on their open/closed status. The schematic shows the LHR door and the back door switches to be commoned and go to the ECU behind the radio but the RHR has a separate feed wire direct to the ECU - so earths on either/both these wires are causing the ECU to operate correctly but closing all the doors brings on the fault condition. It looks very likely that the problem is behind the radio (which is aftermarket but was in the 105 when I bought it) so I will be looking for dislodged plugs etc. before attacking the ECU --more when I can get to it
Greg
 
As mentioned above, my truck has ambulance (barn) type doors (and I appreciate the OP has a tailgate, but my problem started with the rear wipers coming on by themselves.

Then the rear right quarter wiring caught fire.

Long story short, there were broken wires where they go to the doors, joining hands and causing shorts....

All fixed now bar the legacy of overheated wires all through the truck :whistle:

No broken wire or water damage here Clive the door is like new inside and the wiper works correctly with the hatch door closed if one of the rear passenger doors is opened - my money is on the ECU or its connections -- more later
Greg
 
Most problems withe rear wiper has been caused by moisture in the harness plug in the bottom left corner of the rear hatch.
Another common problem comes after changing the radio, or other work in that area. A plug to the ECU (partly) disconnected, or a wire cut or earthed.
Then, third most common, is where the cable flexes between the hatch and body. Either rubbing against earth, or broken.
I can't positively connect any of these 3 with the funny symptoms, but a dislocated ecu plug, or moisture in the plug at the back, can certainly trick the ecu into doing strange things.


uHu, I think you are on the right path with the ECU connections, the radio has been changed (by the last owner) so it could be that there has been disturbance of the connectors to the ECU - that's where I will go next,
Greg
 
Just wondering if you found the solution to the problem of the rear wiper as i am having the same issue
Tried different ECU and auto electrician and neither worked
 
Sorry to say there has been no progress, too many jobs not enough time -- I will post here when I find time to tackle it -- my next step would be the instrument ECU, is that the one you changed ?? it resides behind the radio in the middle of the dash
 
Sorry to say there has been no progress, too many jobs not enough time -- I will post here when I find time to tackle it -- my next step would be the instrument ECU, is that the one you changed ?? it resides behind the radio in the middle of the dash
Yep that was the one i changed but it was from a wreckers, does your lights flash longer when you use your remote central locking?
 
No I don't have any problem or change in the remote locking - just the wiper that only works when a back door is open. Did you have any change in the symptoms when the ECU was changed ??? Regards Greg
 
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