Hi

My rear wiper has taken on a whole new life of it's own. Comes on when it wants to. Sometimes just a few wipes, but other times runs continuously for a few minutes. Strangely enough it only does it when it is wet. Not read anything regarding a moisture sensor in the rear window, but who knows?

Tony

Hello Tony,

These motors seem to suffer from water ingress, so this would be a good place to check first. If all is well there, then it’s worth checking the wiring in the flexible harness section twixt body and tailgate. This is a favourite place for wires to fracture, particularly in cold weather.

Kind regards,

Gareth. 

Hi Gareth

Just looked at the tailgate, looks nice and dry, but unless you strip down the roof lining I can't actually see anything. The wiper starts with the column switch off, so in theory that circuit should not be live. So any break would have the opposite effect of the wiper not working. We have now got some nice blue sky and no rain, I'll see if it behaves itself today. If not I will have to take out a second mortgage and send it in to Audi for surgery.

Tony

Thanks Tony,

If needs be, I wouldn’t be taking it to Audi before spending an hour’s time with a trust local auto electrician. 
Kind regards,

Gareth. 

12 hours ago, Anton8 said:

Hi Gareth

Just looked at the tailgate, looks nice and dry, but unless you strip down the roof lining I can't actually see anything. The wiper starts with the column switch off, so in theory that circuit should not be live. So any break would have the opposite effect of the wiper not working. We have now got some nice blue sky and no rain, I'll see if it behaves itself today. If not I will have to take out a second mortgage and send it in to Audi for surgery.

Tony

 Knowing that I know nowt about audi setups in particular - I bought this car so I no longer have to work on fixing cars ! - feel free to ignore this.... but your statement is incorrect on a large number of cars/applications. The common view that if its in the off position its isolated is often wrong, as many times the switch provides the "earth" (more correctly the 0 volt connection) to enable a circuit to be completed, thus at any point in the wiring before the switch  a "short" to "earth" will provide the 0 volt connection and the item will burst into life !! Without knowing the circuits, your description of the fault fits this scenario perfectly ...  a break in a wire somewhere between the motor and the switch is "earthing" and completing the circuit so the wipers do their own thing regardless of switch position. I wish you luck in finding the offending bit of wire... I'd be looking around the tailgate hinge area myself .....

The trouble is Gareth because I live in the supposedly affluent area of Kent our Indies are nearly the same price as Main Dealers. When I had the cam belt and water pump done the Audi price was £915 and our local guys were £850, so I might as well go to Audi. Also I get a nice valet, MOT for life and the coffee is not bad. Apart from that the receptionist has a figure you would die for. I have booked the car in for Wednesday next week and I will let you know the out come.

Tony

Took the car in. No fault codes, not done it since, rear wash wipe behaving itself, no charge.  A glitch in the system perhaps.

On 1/12/2023 at 2:15 PM, Anton8 said:

Hi

My rear wiper has taken on a whole new life of it's own. Comes on when it wants to. Sometimes just a few wipes, but other times runs continuously for a few minutes. Strangely enough it only does it when it is wet. Not read anything regarding a moisture sensor in the rear window, but who knows?

Tony

Hi Tony my car does the same I think its because its linked to the rain sensor on the front if I have my front wipers on auto it does it first thing in the morning if its wet and during the day when its just started to rain. A dying motor normally manifests itself when the wiper refuses to park the blade in the correct position or won't work at all.

Steve.

Hi Steve

This is exactly what a car techy told me recently.

Tony

These rear wipers have the wash water pipe come up through the spindle, that metal tube corrodes through and you get water ingress into the gearbox, which then corrodes and gets gummed up when the washer fluid dries!

mines been acting up too, sometimes same symptoms as yours, few times either not moving at all or parking in wrong place!

so I’m looking to get a new one when the weather warms up and fitting it myself. (Done them before, awkward bit is getting the trim off without damaging anything!)

1 hour ago, 56Doc said:

These rear wipers have the wash water pipe come up through the spindle, that metal tube corrodes through and you get water ingress into the gearbox, which then corrodes and gets gummed up when the washer fluid dries!

mines been acting up too, sometimes same symptoms as yours, few times either not moving at all or parking in wrong place!

so I’m looking to get a new one when the weather warms up and fitting it myself. (Done them before, awkward bit is getting the trim off without damaging anything!)

Hi if you buy the expensive [£15 trim removal kit] off eBay it makes life damage free except for the panel spring clips which deform easily, upside is you can buy the clips on eBay as well.

Steve.

I’ve got both from fitting OEM blinds to my sons car. Forgot about them until you mentioned it though!

Yes, I have heard that the clips on the tail gate trim are very ferocious

Tony

Cheers Tony