Bonkerzbanks
09-12-2006, 11:23 PM
Hi! I drive a Golf MK4 130 TDi. The drivers side window has just stopped working so I've decided to fix it! All other windows work fine. When operating the switch, there is an audible click of a relay switching on then off. The motor doesn't even attempt to move.
The fault code suggested that the electric window motor was faulty so I opened the door panel and took off the motor for examination. I managed to unclip the PCB and housing from the motor connections and putting 12V on the contacts of the motor whizzes it around like it should. No motor problems here - so much for fault codes! (Well, to be fair it is the first ever diagnostic I've done on any car - ever.)
Next I checked the relay on the PCB which seems also to work just fine - contacts close and short as they should - both directions.
So now I decide to check the power supply at the door controller connector and this is where it gets wierd. (See attached diagram 1) On a multimeter, the voltage shows a steady 12V. An attached lamp illuminates. When the motor is attepted to be actuated, this voltage drops to nothing (lamp goes dark!). Then after an indeterminate amount of time it comes back to life by itself.
I'm guessing that this supply pin for the lifter motor is not a direct battery connection but somewhere goes through a current limiter circuit and I suspect that it is this circuit that is defective. Either that or its just a very bad connection somewhere.
My question is does anyone know where this limiter circuit is or where this supply pin connects to? The current flow diagram suggests it's on track "251" but I think I probably don't understand these diagrams as I have no idea how to locate track "251"...
Any help greatly appreciated!
Paul
The fault code suggested that the electric window motor was faulty so I opened the door panel and took off the motor for examination. I managed to unclip the PCB and housing from the motor connections and putting 12V on the contacts of the motor whizzes it around like it should. No motor problems here - so much for fault codes! (Well, to be fair it is the first ever diagnostic I've done on any car - ever.)
Next I checked the relay on the PCB which seems also to work just fine - contacts close and short as they should - both directions.
So now I decide to check the power supply at the door controller connector and this is where it gets wierd. (See attached diagram 1) On a multimeter, the voltage shows a steady 12V. An attached lamp illuminates. When the motor is attepted to be actuated, this voltage drops to nothing (lamp goes dark!). Then after an indeterminate amount of time it comes back to life by itself.
I'm guessing that this supply pin for the lifter motor is not a direct battery connection but somewhere goes through a current limiter circuit and I suspect that it is this circuit that is defective. Either that or its just a very bad connection somewhere.
My question is does anyone know where this limiter circuit is or where this supply pin connects to? The current flow diagram suggests it's on track "251" but I think I probably don't understand these diagrams as I have no idea how to locate track "251"...
Any help greatly appreciated!
Paul