Electric window problem

[andydunn2]

Ok did something daft and connected my drivers side window switch whilst ignition was on and have blown something as none of the windows work at all now, anybody any idea what might have popped?

This is on a 98 cab but it's the same as any other B4 front the front forward.

Ta Andy

[msh]

Nothing to do with the ignition being on, just coincidence. Something wrong with window control unit or circuit breaker that provides power to it.

[andydunn2]

Originally Posted by msh

Nothing to do with the ignition being on, just coincidence. Something wrong with window control unit or circuit breaker that provides power to it.

Ok by window control unit do you mean the relay?

[msh]

Yeah.

[andydunn2]

Originally Posted by msh

Yeah.

Thanks, the entire circuit is dead with no power to either the passenger side or drivers side switches, although there is power to the central switch so that must on a different circuit. Checked the two thermal fuses that I found and both seem ok so it's definitely leaning towards the relay/control unit at the moment.

Damn car is being a mare just lately, just needed to bleed the brakes and it was going in for its MOT and now this ......

[msh]

You can do a test - short circuiting pin 2 in the control unit socket with pin 8 will provide power to passenger side window. That's presuming presuming that 1998 cab still uses the system which was phased out on other cars with introduction with "A series".

[andydunn2]

Originally Posted by msh

You can do a test - short circuiting pin 2 in the control unit socket with pin 8 will provide power to passenger side window. That's presuming presuming that 1998 cab still uses the system which was phased out on other cars with introduction with "A series".

Seems to be slightly different but I did manage to check supply coming into the relay (Siemens 79FA405, marked 367 on top);

Pin 30 = battery
Pin 31 = negative
Pin 15 = ignition (switched live)

So based on all the above are ok and there is no power to any window I am presuming the relay is the problem, would you agree?

[andydunn2]

Ok, to answer my own question yes there is something that goes pop, there is a fuseable link within the power window relay and yes I had blown it by connecting the switches while the ignition was switched on....

All sorted now though with a blob of solder...

[msh]

Coincidence anyway. That relay should be able to handle 20 amps minimum - you simply couldn't overload it.

[andydunn2]

Originally Posted by msh

Coincidence anyway. That relay should be able to handle 20 amps minimum - you simply couldn't overload it.

Could easily be, these relays are notoriously weak and subject to cold solder so might have been damaged already. I have never run this car as I bought it as a spares/donor car and it has sat for the last 2 years un-covered at the back of my house so not 100% certain what was good or bad on it.