Rain-sensing wipers on my Avant!

[Ross]

I seem to have bought an Avant with rain-sensing wipers! They obviously didn't work for a while, as I always had to use them manually, but of recent they seem to come on automatically - sometimes they even come in in the dry.

Anyone got any ideas?? Dodgy relay? It's happening very infrequently, perhaps one in 5 times i drive it, but the wipers sometimes come on for ~30s and then go off again. Sometimes I turn them off when it stops raining, and they stay on for ~30s... Thought it could be damp but then it occurred when the car had been in dry storage and not got wet in over a month.

Ross

[Evilgoat76]

Check boot hinge wiring loom. Sounds silly but possessed wipers was one of my symptoms.

[Le S2 Audi]

Mine on my coupe did the same thing from time to time... I upgraded the relay to the No99 one and it stopped doing it...

Just an idea...

[Ross]

Any more details on this "no99 relay"? Can't find anything about it... this has suddenly started doing this all the time and it would be good to at least pull the relay so i can drive it in the mean time, and get one ordered (presume this is an audi part?) and keeps my fingers crossed it works.

Oddly enough, I've found i can stop the wipers by turning on the dip beams! If they start going again, flick the lights off and on and it stops them again... very strange.

[Evilgoat76]

Check that loom, in my case it was turning on the rear demister that shut it up not the headlights.

Open the boot and look at the hinges. There are two rubber boots off into the door. One on the right is of no interest, one on the left, take off theplastic hinge cover and peel the boot back. You are looking for cracked or even broken wires in there. You may have other symptoms you dont knwo of too, make sure everything on the back works, lock, lights, demister, washer and wipers.

[Ross]

OK so I peeled back the covers and had a peek, no issues but it looks like the loom has been sliced and taped at the point it dissapears into the boot lid. Am i correct to assume there shouldn't be any joins there?? Perhaps it's an idea for me to check it out a bit more thoroughly... I've got an MOT due in 2 weeks and this is yet another issues to add to my list. Think I need to concentrate on getting the issues with the Golf sorted

[Evilgoat76]

OK so I peeled back the covers and had a peek, no issues but it looks like the loom has been sliced and taped at the point it dissapears into the boot lid. Am i correct to assume there shouldn't be any joins there?? Perhaps it's an idea for me to check it out a bit more thoroughly... I've got an MOT due in 2 weeks and this is yet another issues to add to my list. Think I need to concentrate on getting the issues with the Golf sorted

There shouldnt be any joins. I would have thought the only way this would cause your issue is a short, if the wires are all intact then maybe its not there afterall. Just check everything works to be sure.

[Ross]

OK fitted the No99 relay on saturday morning (thanks Ken!) and it hasn't reoccurred in about 3 hours of driving so fingers crossed. Don't want to think about why the loom has been butchered at some point, if the replacement relay hasn't solved the problem I'll be having a look at the joins...

[Ross]

Just to finish up the thread - covered 200 miles through the week with no reocurrance, and as a bonus the autocheck has stopped flashing every 10s when I've got the lights on! Odd how the lights were related (?)