Bizarre wiper problem! [Archive] - SaabCentral Forums

: Bizarre wiper problem!


Matt Phelps
12th November 2002, 09:34 AM
I found a strange fault with my wiper this morning. It wouldn't turn off! I had it on for quite a while and then went to switch it to intermittant wiper and it continued at the usual speed instead. It would go faster but no slower. I then found I couldn't switch it off either.

Eventually I squirted the screenwash and then went up and down through all the positions several times and it started working correctly again!

Anyone come across this before?

BillJ
12th November 2002, 10:37 AM
Quite possibly a fault with one of the headlamp wiper motors. If the reverse blocking diode fails, then the headlamp wiper can drive everything attached to the wash/wipe switch. If the self-park on the same motor then fails too, then it will run forever and keep the washers and wipers running forever too! The only way to stop it in this extreme situation, as I found out, is to remove the fuse for the headlamp wash/wipe. See here (http://www.saab9000.com/procedures/electrical/headlampwiper.html) for more information.

Matt Phelps
12th November 2002, 12:23 PM
Really? The windscreen wiper is connected to the headlamp wiper?

BillJ
12th November 2002, 01:48 PM
When you pull the wash/wipe switch, the switch feeds the windscreen wiper. The same switch feeds the washer pump too and also the headlamp wipers. So actually, it is true to say that both are connected to the wash/wipe switch. If something feeds current to that switch (as the headlamp wiper motor can do if the diode goes short), then that will feed voltage to everything connected to it.

Matt Phelps
12th November 2002, 01:55 PM
Right, maybe a quick look at the headlamp wipers then to see if they are working or not. Unfortunately (or fortunately I suppose) I couldn't reproduce the fault on the way home tonight.