while driving along in xj40 sovereign 1988 , i pressed the city safe central locking button in the centre consol , now the two front windows dont work and the central locking dont work off the key , has anyone came across this ,

need someones help thats smarter than me thanks ,

ok an update central locking is now working , but both my front windows dont work - ideas anyone

 

Hi Stuart,

I was having a look at schematics to see what might be up, and I see you got the door locks working. Was that just a case of having to manually cycle them all?

Test every fuse in the car with a testlight to make certain you have power through each one, and make certain that nothing else on the car (interior lights, as one example) is affected...if all else if fine other than the front windows, I can help from there.

 

hi , sorry didnt get back sooner , trouble with pc too ha ha ,

eh av tested all the fuses and everything else is fine and as you said i manualy cycled the locks ,

not sure if mines xj6 or xj40 same pics in the book for both !!
but am sure you will tell from the pic , any advice would be appreciated

kind reguards

from scotland

 

1988 XJ6= 1988 XJ40 1988 Sovereign, no worries there.

So EVERYTHING works except the two front windows, and you're sure all the fuses are OK?

 

yep tested em all

 

The only things not working are the two front windows? Did you try the offside window from its' own switch? Is car RH drive?

 

OK Stu, I gotta go. Why the questions are important is that when I look at the wiring diagram, I am looking for common denominators. It leads us both astray if I'm looking at the wrong circuits, and I don't want to tell you that the CPU is bad until I give you some places to test first.

 

your help is appreciated mate it is a uk car so r/h drive , couldnt see much on the wiriing my self , everything seems to be working apart from them front two windows , and it doesnt work off the passenger button either , could it be relays ? and where are they

thanks mate

 

Hey Stu,

Yeah, this is a bit sticky. The relays are built into each switch, and the two front switches each get a separate power feed from their respective fuse boxes. If you are not getting any click at all when you try either front window switch in both directions, the relays probably have no ground path.

The schematic does not show internal ciruitry for the Central Microprocessor Unit(abbreviated CPU), so it's a little sketchy on how to test it for ground signal to the driver's switch pack. If wou want to pull the driver's interior door panel off and you have a voltmeter/ ohmmeter to test with, we can figure it out. My conclusion from the diagram is that this is a CPU or driver's switchpack fault and testing is required.

The panic button on the dash is not the cause of the problem, even though that is what started the event. It will likely still work if you try it with rear windows and sunroof open: all that switch does is provide a momentary ground to the CPU, and the CPU tells everything to actuate. It just isn't talking to the front windows. In that respect the panic button works the same as the microwsitches on the doorlocks to send a ground and close everything up. So these CPU inputs are not the problem, it's a missing output or a driver's switchpack that isn't using the output correctly. That's where it looks to me like where you are at.

 

well i will get on it over the next few days , will let you know the out come , thanks again for your help