VW electrical problem

Padington

Hi guys,
I've spent the day working away at my VW Bora and I have a question that I hope someone might be able to answer.

Basically a couple of days ago I went to open the car via the boot, but she would not open and I subsequently noticed that the interior lights and electric mirrors were also not working. I've since got the Haynes manual and realise that these are all on the same circuit.

I began by opening the boot from the inside and taking apart each of the boot locking components as I reckon there is a short somewhere and I'm sure (by testing) that it is not the electric windows or interior lights.

I've tested the boot components one by one and no joy in finding the short yet; but here's my question:
I've attached a picture of the key-lock mechanism for the boot and also the electrical switch that is attached to this unit that opens and closes the car upon turning of the key.
With regards to the electrical switch (shown in my hand), this is able to turn both left and right but only unlocks the car for me and I am not able to lock the car by flicking this with my hand. Should I be able to lock the car via this switch?


Many thanks for your help.

nogoodnamesleft

If you had an electrical short in the car it is very likely that you have a blown fuse. As you mentioned the central locking, elec mirrors, interior lights etc are on the same circuit and are not working (indicates an absence of 12VDC supply).

My advice would be to check the fuse panel on the drivers side from memory this particular circuit has a 15Amp fuse. Replace if blown and investigate using a multi-meter on the suspected cause of the fault.

Padington

Cheers for the reply nogoodnamesleft,
Yup the fuse is blown and only blows when I turn the key in the boot.
Hence I've taken apart the boot electrical connections.

What I did then was to connect the multimeter (on current reading mode) across the fuse box connection thus completing the circuit and I got a helper to twist the key in the boot to see could I notice a surge in current..unfortunately I couldn't see anything untoward here. So either my multimeter didn't pick up the surge or the problem might be somewhere else.

I'm about to check the earth point back there...

Waterson

Hi Paddington,
You need to be thinking in terms of voltage as opposed to current with regards this problem. A short circuit is most likely causing the fuse to blow, so look for areas where you could potentially have wires chafing (grommet holes in bulkheads etc. Use your meter to back probe the circuit starting at the electrical connectors, back to the earthing points to find areas of high resistance that would cause the fuse to blow. Best of luck.
Oh and check the Comfort Control Module under the passenger carpet isnt sitting in a puddle of water. This is linked toa ll the components youve listed and can short out due to water ingress.

Padington

Waterson, cheers for your advice.
By fluke last Sunday I managed to find that a problem (it might not be my only problem) lies in the rubber casing that covers the wires running up along my boot.
There must be a wire cut or worn inside there as I have been able work the circuit again after some wiggling. I plan on opening the casing this Sunday and seeing what the story with the wires inside there is.

Thanks for your advice and I will have a look at the comfort control module anyway to check.

dieselbug

"What I did then was to connect the multimeter (on current reading mode) across the fuse box connection thus completing the circuit and I got a helper to twist the key in the boot to see could I notice a surge in current..unfortunately I couldn't see anything untoward here. So either my multimeter didn't pick up the surge or the problem might be somewhere else. "

Most dmm"s will only handle 10amp max current flow.(some top of the range will do 20 amp) If the circuit is blowing 15amp fuses your dmm wont handle it (fuse removed I presume). Probably blown the fuse in the dmm if its not fried.