1989 XJS V12 windows/top inoperative
The car had been stood for a good while when I bought it and finally got this running but neither front or rear windows will raise Nor WILL the top (hood). I understand handbrake must be applied for top raising but door windows baffle me as I have removed panel and applied power direct to motors without success.
I suspect I may have 2 different problems here although they both seem to suggest ground issues. The door frame itself seems to have a small amount of current passing through it when I touch with the test light (ignition on) and both wires to the motor are powered up without pressing window switch.
I do not know how to test top module or even if problem is connected to front windows anyway. I get brief movement in back 1/4 windows by stabbing across relay
Any idea from super sparks people appreciated.

 

Are you saying there is voltage reading when measured between the car body and the door frame?

If this is correct you have a grounding issue.

 

When I test the door window motors (and the door panel is off) I unhook the leads to the motor and apply my 12V power supply leads to the motor to test up and down. If you do not unhook the leads. If this works and the windows do not when the ignition switch is on, then it is probably the control switch on the ski slope (the first thing to check before removing the door panels). Clean off the spades of the switch with an abrasive first.
Ken in WV

 

Just to add to Ken's advice, these switches can be dismantled and cleaned out. I've found a remarkable amount of crap inside one preventing, in my case, the top electrics working.