Had '90 900i convfor nearly 3 yrs, drivers door window has just decided to open on ign on! Either have to drive with finger on down button or remove switch, replaced switch, no joy, checked relay base under rear seat term 15 pos term1 neg, relay in,turn ign on, hear relay change and window opens......??
Electric windows
1 - 5 of 5 Posts
Ta Zolf, windows down while driving!!! ok for 3 days of the year, but I like the rain on the outside. Switch bank is in centre console, checked no shorts, beginning to suspect diode on relay is duff. Will dive in under rear seat tomorrow (test is rained off at mo)!
Joined
·
2,587 Posts
Hey there,
I don't think the relays use diodes for supression. If they were to use diodes, the relays would have be polairty specific. Generally, there are preferred arrangements for wiring of relays but it is not polarity orientated. In the relays I've encounted, there is a low value resistor in parrallel with the winding to act as emf supression.
I'm not confident that the relay will be your cause of ire! I'm not to know the condition or history of your car but having rebuilt the switch assy on my car, I remember the loom path in the centre of the car as not being very ideal.
I read in these forums occasionally of wiring abnormalities for one fault or another and generally am left with impressions of previous owners and their botch ups, wiring faults from install jobs, alarm configs etc. all seem to be coming home to roost, so to speak.
Being a conv, is there any chance of corrosion effects from a possible deluge of rain in the past perhaps or similar?
Was the switch you installed new or used? ( TAKE 2...Did you replace the switch?)
Just some thoughts......
Cheers
14/09/05: I stand corrected. I went and looked in the bible and observed the arrangement being different for the convertables. Sorry for crapping on.
P.S. The Ashes are yours!
I don't think the relays use diodes for supression. If they were to use diodes, the relays would have be polairty specific. Generally, there are preferred arrangements for wiring of relays but it is not polarity orientated. In the relays I've encounted, there is a low value resistor in parrallel with the winding to act as emf supression.
I'm not confident that the relay will be your cause of ire! I'm not to know the condition or history of your car but having rebuilt the switch assy on my car, I remember the loom path in the centre of the car as not being very ideal.
I read in these forums occasionally of wiring abnormalities for one fault or another and generally am left with impressions of previous owners and their botch ups, wiring faults from install jobs, alarm configs etc. all seem to be coming home to roost, so to speak.
Being a conv, is there any chance of corrosion effects from a possible deluge of rain in the past perhaps or similar?
Was the switch you installed new or used? ( TAKE 2...Did you replace the switch?)
Just some thoughts......
Cheers
14/09/05: I stand corrected. I went and looked in the bible and observed the arrangement being different for the convertables. Sorry for crapping on.
P.S. The Ashes are yours!
Dug out the relay, thanks to Saab in Southampton who copied the wiring out of the manual, I traced that just with ign on I was getting 12v+ on term 15 on relay with neg on term 1. As that made window open I reckon somehow it's leaking past and operating coil when it shouldn't be, so ordered another one from Sweden. I've been lucky so far in 3 yrs had it, just gone over 50k so it was in real good nick, last owner was my mates elderly dad, 72, who only tootled out shopping in it! The heater icky went under the dash, that was fun! And head gasket went last year, but thats been it, so can't moan.
1 - 5 of 5 Posts
