Another Rear wiper won't stop thread....

[davegsm82]

I've done what every sensible poster should and checked the other threads, followed all the advice and am still baffled by the information that doesn't seem to tie in anywhere. 

 

So, the Mrs has a 2012 Yeti, on which the rear wiper won't stop, unless you remove the Fuse (number 6). 

 

It doesn't matter what mode the wiper stalk is in, both front and rear can be off-int-on-fast and on-off. No combination at all makes the rear wiper stop. 

Ive been through the menu in the maxidot and turned off the tickbox for rear wiper, that makes no difference either. 

It is permanently stuck on intermittent wipe, once every 10 seconds. Other's have suggested this is the motor, but I similarly can't see HOW this can be at fault, I understand vehicle electrics very well, usually if the switch inside the motor fails then it will be on constant, i.e. doesn't stop at all, never mind being stuck on intermittent.

I've not inspected the motor yet, is there any electronic control inside of the motor? or is it simply the motor and the end/stop switch just like it used to be?

Cheers, Dave.

[freedie]

This will happen if the wiper stalk is pushed away from the steering wheel to wash the rear screen and not pulled back after release. In other words it is now stuck in the "rear wiper on" position. Worth checking, as the motor must be OK if it moves as you describe!

[davegsm82]

55 minutes ago, freedie said:

This will happen if the wiper stalk is pushed away from the steering wheel to wash the rear screen and not pulled back after release. In other words it is now stuck in the "rear wiper on" position. Worth checking, as the motor must be OK if it moves as you describe!

Yep, this is exactly why I'm massively confused. It doesn't matter WHERE the stalk is, forward, backward, up,  down, it just does NOT stop working in intermittent mode. 

 

You can push it all the way back to wash the rear screen, which works fine, fluid comes out, wiper works on constant for about 5 seconds (3-4 wipes) then you pull it back to the normal position, or even to the front screen wash position if you want to be doubly sure, and it STILL wipes every 10 seconds.

[freedie]

Right. I did realise you had tried everything. I have released the front screen wash and experienced the stalk clicking through to the rear wiper position; but... you have obviously taken everything into account (including the maxidot). So it now sounds like a mechanical fault with the wiring sensor in the the clockspring area. Good luck.

[J.R.]

To answer your question re the motor, it has a permanent 12v live feed, a chassis ground connection and a twisted pair canbus connection, it has a canbus microcontroller on the PCB and recieves all its commands from the body control module in response to inputs from the column stalk switches.

 

To rule out the motor you could remove the canbus wires from the connector & see if it then remains static but that would be fiddly & would generate a fault code although probably not a MIL light, a VCDS scan would reveal if there is an implausible signal from the stalk switch or a canbus comms error.

 

I have a vague recollection that there might be a programming option for the BCM that does something like permanent intermittent rear wipe, there are some strange options, perhaps something has become corrupted.

 

[boxman]

I had the same problem  recently but found if I flick the switch on and off quickly it usually cures it having said that I have mostly  avoided using  the rear wash/wipe since     

[davegsm82]

17 minutes ago, J.R. said:

To answer your question re the motor, it has a permanent 12v live feed, a chassis ground connection and a twisted pair canbus connection, it has a canbus microcontroller on the PCB and recieves all its commands from the body control module in response to inputs from the column stalk switches.

 

To rule out the motor you could remove the canbus wires from the connector & see if it then remains static but that would be fiddly & would generate a fault code although probably not a MIL light, a VCDS scan would reveal if there is an implausible signal from the stalk switch or a canbus comms error.

 

I have a vague recollection that there might be a programming option for the BCM that does something like permanent intermittent rear wipe, there are some strange options, perhaps something has become corrupted.

 

 

Thanks JR, I've got VCDS but haven't tried plugging in yet, do you know which module I would need to interrogate? I'd assume it would be the equivalent of the old comfort control module, do they call that the Body Control Module now? 

If the stalks are a CANBUS module of their own, is there a channel where I can see the stalk status?

 

2 minutes ago, boxman said:

I had the same problem  recently but found if I flick the switch on and off quickly it usually cures it having said that I have mostly  avoided using  the rear wash/wipe since     

 

I've tried working the switch backwards and forwards loads, but it seems to make absolutely not a jot of difference, it doesn't even seem to recognise me turning it on, i.e. from off to on, the wipe could be 1 second or 10 seconds later. 

[davegsm82]

Additional info.

Plugged in VCDS, in Central electronics - channel 18 - Gives info for the front Wipers, switch position etc, but can't find any channel that mentions the rear wiper, only the rear wash, which of course activates when you push the stalk towards the cluster.

 

In long-coding there's an option for "rear wiper on with intermittent front" and "rear wiper on with constant front", both were enabled, so I disabled them, saved it, backed out and there was zero difference at all. Rear wiper just carries on regardless. 1 wipe every 10 seconds, 3 wipes with rear wash activation. 

If anyone knows where I can check the rear wiper switch positions on VCDS I'd love to hear from you.

 

[davegsm82]

Still having this issue, plugged in VCDS and checked the steering wheel module, in "advanced ID's" There's a status indicator for the rear wiper. 

The status indicator mirrors the stalk position exactly, so if it's ON (pushed away from driver) it says 'Activated' (or whatever) and when it's OFF, i.e. pulled towards driver it says 'Not Activated'. 

The rear wiper carries on wiping regardless, it JUST. WONT. STOP. So I've had to remove the fuse. 

I have also replaced the wiper motor with a good used item, just to rule that out and it's not made any difference. 

[J.R.]

Try my suggestion of disconnecting the canbus wiring from the motor.

 

I have no recollection of writing the posting!!!!

[Llanigraham]

15 hours ago, davegsm82 said:

Still having this issue, plugged in VCDS and checked the steering wheel module, in "advanced ID's" There's a status indicator for the rear wiper. 

The status indicator mirrors the stalk position exactly, so if it's ON (pushed away from driver) it says 'Activated' (or whatever) and when it's OFF, i.e. pulled towards driver it says 'Not Activated'. 

The rear wiper carries on wiping regardless, it JUST. WONT. STOP. So I've had to remove the fuse. 

I have also replaced the wiper motor with a good used item, just to rule that out and it's not made any difference. 

Have you checked the wiring where it bends between the body and hatch?

[davegsm82]

21 hours ago, J.R. said:

Try my suggestion of disconnecting the canbus wiring from the motor.

 

I have no recollection of writing the posting!!!!

 

7 hours ago, Llanigraham said:

Have you checked the wiring where it bends between the body and hatch?

Hi Guys, thanks for the suggestions. 

I did check the wiring but didn't get to do any voltage or continuity checks at the time, as it was heaving down with Rain. 

Ok, so I replaced the motor, which made no difference whatsoever. But because I now have a spare motor, I thought I'd have a play around with it on the bench. 

I've no reason to think that it's not CANBUS, because when you look at the wiring it certainly seems to be CANBUS wiring, however;
If you hook up power to the 0V and 12V pins nothing happens. 
If you touch pin 2 to ground it does a wipe, or hold it on ground then the motor acts like the one in the car, 1 wipe every 10 seconds. 
If you leave pin 2 connected to ground, then connect pin 3 to +VE, the motor runs continuously then runs on for a few wipes once you disconnect pin 3.

This operation is almost like what you think you could expect from a standard motor, not a canbus one. It's like grounding pin 2 signifies 'on', and as if pin 3 should be connected to the screenwash motor to wipe continuously when you wash the rear screen. 

Perhaps these motors are BOTH canbus and traditional operation? and because of this, perhaps the fault with this car is that the pin 2 wire is shorted out somewhere, meaning it can't read the CANBUS and is essentially running in more traditional operation sort of 'by accident'. 

 

Cheers, Dave. 

[davegsm82]

Just by way of an update;

Did some checks on the car at the weekend, this motor (i'm not saying ALL motors) is NOT Canbus, it's not connected to canbus, instead it's connected directly to the screenwash motor and the BCM as found out by another helpful forum member who must have access to diagrams. Part number of this motor is 5J7 955 711 C PL9 - as fitted to a 2012 Yeti.

This also supports what I thought was happening when I've been playing with this motor on the bench. 

Currently it's pointing to either the washer motor OR the BCM being faulty. I'm leaning towards the BCM because it drives the motor with 'Bipolar output drives' (transistors) from signals generated by the stalk, and the screenwash motor works when the rear washer fuse is installed (it's a dual output motor, so since it works one way it SHOULD work the other way).  It points to one of the transistorised outputs being faulty in the BCM.

 

Regards, Dave. 

[davegsm82]

Located and repaired this fault, found short circuit beneath the drivers side headlight. 

Repair details here;