Does anyone have a wiring diagram for the interior of the MK1 yeti? I'm trying to find out where the short circuit is likely to be on my wife's car that's causing the rear wiper to run continuously. 

It will not be a short circuit, all the wiring diagram will show is a live, earth and a twisted pair for the canbus.

 

The problem is likely to be the circuit board in the motor assembly.

 

Another possibility is corrupted programming of the body control module, have you recently had a flat battery or sluggish cranking?

Edited 15 December, 20205 yr by J.R.

1 hour ago, J.R. said:

It will not be a short circuit, all the wiring diagram will show is a live, earth and a twisted pair for the canbus.

 

The problem is likely to be the circuit board in the motor assembly.

 

Another possibility is corrupted programming of the body control module, have you recently had a flat battery or sluggish cranking?

Hi J.R. 

 

I can assure you that either there's a short in the wiring loom or there's a fault in the BCM that's shorting that line down to ground. If you read the last post on my other thread about the rear wiper not working you'll see I've investigated the operation of the wiper motor so today I checked for shorts;

 

Multimeter connected at the motor plug;

 

 

Direct short to ground with both ignition on and off, irrespective of stalk position.

 

Disconnected this plug inside the D pillar behind the trim panel;

 

Short circuit gone.

 

 

So, my next question is, where is the BCM on the yeti, and if someone has a wiring diagram, can you please tell me where these wires connect to on it?

 

Catch you after my spag bol.

OK, so judging by your photo the short is between the brown earth wire and the white wire nearest to it? 

That white wire becomes a green/red one at pin 2 of the five-way connector you've found. From there it heads forward to the BCM, pin 2 of the white 52-way connector. At some point before getting there, it also tees off to the washer pump motor, so there's the possibility of a short in that leg of the wiring too. Do the windscreen washers work, front and rear?

 

BCM is located 'below the right dash panel' on RHD cars. A Yeti owner is likely to be able to help with access/location much more than that, I trust!

 

 

5 minutes ago, Wino said:

OK, so judging by your photo the short is between the brown earth wire and the white wire nearest to it? 

That white wire becomes a green/red one at pin 2 of the five-way connector you've found. From there it heads forward to the BCM, pin 2 of the white 52-way connector. At some point before getting there, it also tees off to the washer pump motor, so there's the possibility of a short in that leg of the wiring too. Do the windscreen washers work, front and rear?

 

BCM is located 'below the right dash panel' on RHD cars. A Yeti owner is likely to be able to help with access/location much more than that, I trust!

 

 

Funny you should mention the washers, the rear DOES work, but the fronts windscreen wash fluid has just recently stopped working, although the headlight washers DO work when the stalk is pulled towards the driver. The rear wiper operation has been faulty ever since we've owned the vehicle (about 3 months), the previous owner had removed the fuse to hide the fault.

I should mention that BOTH white wires appear short circuited to ground, which is why the motor is running all the time. 

On the wiper motor, it looks like the pinout is as follows;
1 - Ground
2 - Intermittent wipe (when connected to ground)
3 - Constant wipe (when connected to 12V, AND when pin 2 connected to ground)
4 - +12V

It's pin 2 at the washer motor that I need to trace out, looks like pin 3 is the one that goes directly to the washer fluid motor, could you please trace that other wire for me? I really appreciate your assistance with this. 

Regards, Dave. 

2 minutes ago, davegsm82 said:

looks like pin 3 is the one that goes directly to the washer fluid motor

Actually it's both, the pin 3 wire becomes green/white at pin 3 of the five-way connector on its way to pin 43 of the black 52-way connector at the BCM. En route it tees off to the other side of the washer motor to the aforementioned wire.

3 minutes ago, Wino said:

Actually it's both, the pin 3 wire becomes green/white at pin 3 of the five-way connector on its way to pin 43 of the black 52-way connector at the BCM. En route it tees off to the other side of the washer motor to the aforementioned wire.

Ok, that's really helpful, I hadn't expected that. 

Possibly a stupid question, but are there 2 separate motors for front/rear screenwash or is it a standard single (dual output) motor?

Thanks, Dave. 

2 minutes ago, davegsm82 said:

Ok, that's really helpful, I hadn't expected that. 

Possibly a stupid question, but are there 2 separate motors for front/rear screenwash or is it a standard single (dual output) motor?

Thanks, Dave. 

I think it's one motor that runs in opposite directions to send water to front or rear. One (water) input, two outputs. Can't visualise the internal details TBH!  

 

Unplugging either the white 52 way, the black one, or both while checking for shorts at the rear wiper should tell you whether the fault is on one or other of the wiring runs, or the BCM itself (I think, but it 's a bit late for thought).

4 minutes ago, Wino said:

I think it's one motor that runs in opposite directions to send water to front or rear. One (water) input, two outputs. Can't visualise the internal details TBH!  

 

Unplugging either the white 52 way, the black one, or both while checking for shorts at the rear wiper should tell you whether the fault is on one or other of the wiring runs, or the BCM itself (I think, but it 's a bit late for thought).

The pumps are odd little things, the impeller spins backwards or forwards to send the water to the back or front screen, the outputs have a little spring loaded non-return valve which stops the washer fluid - A- draining back to the tank under gravity and - B- stops it being sucked back by the pump when it's going in the opposite direction. I dissected one a long time ago and it was a curious but ingenious design.

All of this is pointing to there being a connection to the front screenwash not working. perhaps there's a fuse or something I've missed, although it seems very unlikely as I checked every single fuse previously. if the motor was faulty then it wouldn't wash the rear screen, so I can't see why it won't wash the front. 

Regards, Dave.

Have just been out and checked a couple of things. 

With the fuse out, there's no washer activity at all. 
With the fuse in place, the rear washer works. 
The front washer does not work, but you can hear a high pitched sound from the BCM inside the dash the first time you pull the stalk towards the driver, each subsequent time you don't hear anything so I guess the BCM is faulting out, either because it's knackered OR theres a short elsewhere. 

I did a scan of the BCM and found a fault code:

1 Fault Found 
00897 - Windshield Washer Pump (V5) 
            012 - Electrical Fault in Circuit
             Freeze Frame:
                    Fault Status: 01101100
                    Fault Priority: 3
                    Fault Frequency: 5
                    Reset counter: 46
                    Mileage: 180079 km
                    Time Indication: 0
                    Date: 2015.04.03
                    Time: 08:05:19

The mileage corresponds to the current odometer reading, the date isn't correct, so I can only assume that was maybe the first time it ever happened.

I'm going to bet that the BCM is faulty. 

Regards, Dave. 

12 hours ago, davegsm82 said:

I'm going to bet that the BCM is faulty. 

I think that's a bit hasty and relatively unlikely to be honest.

 

I would proceed to try to eliminate each wiring leg until you run out of candidates.  

Take off battery negative first to be safe from upsetting anything, then unplug washer motor, retest at rear wiper motor for shorts to earth from either white wire. If still present, unplug one of the black or white 52 way connectors from the BCM, etc.

 

 

2 hours ago, Wino said:

I think that's a bit hasty and relatively unlikely to be honest.

 

I would proceed to try to eliminate each wiring leg until you run out of candidates.  

Take off battery negative first to be safe from upsetting anything, then unplug washer motor, retest at rear wiper motor for shorts to earth from either white wire. If still present, unplug one of the black or white 52 way connectors from the BCM, etc.

 

 

 

Indeed, I'll be checking all possibilities before I bite the bullet and shoot for the BCM. I just have a gut feeling that the output from the BCM is faulty. Looking around on a few site's I've seen people having to replace output driver IC's in the BCM which I'm comfortable to do as I'm an electronics engineer. 

Even if the BCM is faulty I still have a gut feeling that there's an intermittent short somewhere else, as I'm positive the outputs of the BCM won't just randomly fail. 

I'll report back once I find out more, that could be a while as this is the Mrs's car, and the headlight washers also soak the windscreen so the impact to her is negligable and she's never eager to give me the car for diagnosis!

Thank you again for your assistance. 

 

Have located and repaired this fault, turned out to be a short under the driver side headlight. 

Repair details here;
 

 

Modern cars eh!  A fault at one end of the car and the repair at the other.  Glad you got it sorted though.