Wash-wipe electrical madness..

And for my car's next trick..

I went out to it in the garage this evening, put the key in and turned it on... and the washer and wipers started going constantly! I double checked and the wiper stalk was in the off position and not trapped pulled towards the wheel.. So I figured the switch must have a problem so I turned the car off and removed the wheel and the plastics around the steering column and unplugged the stalk.

The washer and wiper still went constantly with the ignition on!

I pulled the fuse for the wiper motor. Still the wash and wipe continued..

Only when I pulled the fuse for the washer pump did the washer stop. However the wipers continued some more..

I noticed that if I switched the wiper stalk through the positions Off, to slow, to fast then the wipers went from going fast through slow and eventually off with the wiper stalk in the lowest position on the stalk.. thats backwards!

Its like there is a short somewhere between a switched ign-on 12V and the wire that would come out of the wiper stalk to demand a wash/wipe..

Then there is the confusion of the wipers that run fast when off and off when set for fast, presumably its back feeding 12V through the resistor network that controls the speed?

I can see that I'm going to have a difficult relationship with this car!

If anyone has any ideas as to where to look first then please let me know. I'm not at all familiar with this car yet. If there ate any known trouble spots with this sort of thing then I can look there first.

Ruddy thing! Thanks for any help you can give!

The wash/wipe circuit is controlled by the "Central Accessory Unit" and is activated by 12v being applied to pin 7 of the CAU via the stalk switch.
It might be worth disconnecting the battery, leaving it off for, say a minute or so, reconnecting it, and seeing if the fault has disappeared.
Worth a try.

The wash/wipe circuit is controlled by the "Central Accessory Unit" and is activated by 12v being applied to pin 7 of the CAU via the stalk switch.
It might be worth disconnecting the battery, leaving it off for, say a minute or so, reconnecting it, and seeing if the fault has disappeared.
Worth a try.

Thanks for the info John. Its actually reassuring to know that its not just a dumb wiring circuit as for that to play up its very worrying. (Not that its not worrying of course that a probably irreplaceable box of tricks isn't also playing up!) I'll go and take the battery disconnect out of it now and leave it overnight. ... must remember to put the jack key in the glove box before I turn it back on..!

i had this on my gta turbo, turn on the ignition and the wipers started on thier own and would'nt stop. turned out to be a bad multi plug conection. on the gta there is a multi plug on the loom by the washer bottle that feeds the washer pump, clean contacts fit back together, problem fixed. that was after i had bought a new wiper stalk switch which had no effect its always bad connections and poor earths on alpines. do the simple things first and that usually fixes the problem.