Rear Wiper

[Tribonnie]

Hello all .....

I have Octavia 2 2011  1.8T

 

Rear wiper has had random intermittent failure for couple of months, finally failed

Taken off motor and taken off cover, all very clean inside 

12 volt battery connected across terminal and motor turns and all gears work

Replaced with lubrication on wiper drive shaft

Still not working, fuse Is good

So ...... possible steering column switch

   Front wipers all ok

   Rear screen washer ok

Any ideas on what to check ? ? ? 

Are there any connectors to the rear tailgate that could be faulty

Any way to check column switch

 

thanks Richard

 

[Guest]

You didn't say you checked for voltage at the motor connection.

 

If rear washer activates the signal is fine from column, I'd check for voltage at the motor and work backwards until you find the bad wire/connector/relay.

[TheClient]

I'd check the fuse again. It's caught scores of people out before. What position do you think the the rear wiper fuse is at?

 

Rows down from top and position number left or right? What is its rating? Also once you know the fuse location 100% check fuse with multimeter not only visually. Or put a new one in. 

[Tribonnie]

Hello, thanks for reply

checked the fuse with meter all ok

the problem I have in tracing wiring, there is only 2 inches or so before wire goes in loom

no easy way of tracing back to switch

was looking for any guidance on connectors etc between motor and switch to check

Richard

 

[TheClient]

Ok. I understand,  but which position have you been checking and what was the rating? From memory, rear wiper is a stand alone fuse, so probably wouldn't impact anything else. 

 

I.e. you are probably looking at a fuse on 6th row down from top. But what position from left or right as you look at fuses?

 

 

Edited 25 September, 2020 by TheClient

[Tribonnie]

Hello, fuse is number 41 and rated at 15a

pretty sure it is correct on and checked fuse

short of stripping out all trim and tracing back loom wiring between motor and switch just looking (hoping) for guidance as to where any connectors are

 

thanks Richard 

[Guest]

BTW re checking for voltage at motor connector.

 

Be advised I'm fairly confident it doesn't function with the tailgate open so you'll need to work around that inconvenience.

[Tribonnie]

Yep read that to, tailgate open shows on dash so that switch working

What makes things worse, went out this morning and it worked

Now the bloody thing dosnt

So guess I will have to pull out carpets and trim and trace wiring

Thanks ..... Richard 

[Guest]

With it switched on try banging and wiggling anything you consider likely to be the path from the motor forwards (trim, carpet etc), you may get lucky and find the general area with the intermittent connection.

[J.R.]

21 hours ago, Tribonnie said:

the problem I have in tracing wiring, there is only 2 inches or so before wire goes in loom

no easy way of tracing back to switch

was looking for any guidance on connectors etc between motor and switch to check

Richard

 

 

I dont think you have appreciated how the motor works, it is a canbus node, the only wiring is  12v positive and earth and a twisted pair of canbus wires, your stalk switch is an input to the body control module which interprets it and sends a coded signal via canbus to all the various modules, door controllers, rear wiper, lights etc.

 

If you bench tested the motor you must have done so downstream of the PCB containing the micro-controller and unless you disconnected it you may well have destroyed it especially if you reverse biased the output.

[TheClient]

It is 41 and it is 15A the point I was making is that many times people don't realise the fuse layout schematic is reversed right to left.

 

So assuming you do have power at the fuse, per @J.R. how did you test it out of vehicle?  I have a failed rear wiper in an estate that became very inteermittent, I think it was a PCB issue rather than motor / brushes as that all looked good. And a new motor fixed it.

 

It may not be your wiring!

[J.R.]

Very very unlikely to be the wiring when there are so many other usual suspects.

 

I repaired mine, took me a couple of goes because each time it would be running freely it would later slow down on the vehicle under load, then it behaved for quite a while but played up again and ultimately failed while I was delivering it to the new owner, I did not mind the €30 I knocked off the price for him to buy a new one but was embarrassed and given how much time I had spent, repairing it as is my vocation was not in this instance one of my better decisions.

 

And I didn't spend any time chasing wiring that didn't exist!

[Tribonnie]

Hello again, tested motor off the car with independent 12v battery

Ah ha didn’t realise this is canbus
I kinda understand canbus but in theory only, no practical experience
Am I right to assume that everything on the tailgate, bulbs and motor are nodes so if bulbs etc are working ok it is likely the wiring is good.

Richard 

[J.R.]

From memory the canbus controller on the wiper motor PCB only controls the wiper motor.

 

It would be worth you checking the cable cores under the rubber bellows of the door loop in case any have fractured, the canbus ones are a twisted pair and specific colours, beware that speaker wires are also a twisted pair but I dont think there are any in the rear hatch.

 

All you can physically check wiring wise to the motor loom connector are the two large conductors, one should have good earth continuity, the other should be 12v when ignition switched on.

Edited 26 September, 2020 by J.R.