Hi all,

The reverse light on my mk2 ghia 2007 died, naturally I changed the bulb to no avail, I started doing some tests and discovered that the issue was that the reverse bulb holder worked just fine on the fog light so thus led me to believe the switch had failed, I changed the switch and unfortunately still no joy. I'm sure I've checked for any fuses that could be to blame but if anyone knows of one that would cause this then that would be appreciated! Otherwise I'm leaning towards damage to the wiring somewhere if anyone knows a good place to start looking! I also noticed the rear wiper no longer flicks when I engage reverse with the wipers on! Thanks!

Start by checking the connectors and wiring of the GEM and Fusebox in the passenger footwell. Look for signs of water ingress and/or greenish corrosion of the connector pins.

If the rear wiper is also not activating when selecting reverse the problem has to be either the GEM unit or the wiring between the GEM and the reverse light switch. The fault is not at the back of the car, or with the lamp holder.

13 minutes ago, unofix said:

Start by checking the connectors and wiring of the GEM and Fusebox in the passenger footwell. Look for signs of water ingress and/or greenish corrosion of the connector pins.

If the rear wiper is also not activating when selecting reverse the problem has to be either the GEM unit or the wiring between the GEM and the reverse light switch. The fault is not at the back of the car, or with the lamp holder.

Lovely ill get on that, just wondering where is the GEM? I've only had this car a few weeks so I am not familiar! Also if I have to replace the GEM is that something that's easy to do like plug and play or does it needs coding to the car? Thanks!

49 minutes ago, SilverMk2Ghia said:

just wondering where is the GEM?

GEM = General Electronic Module. It is part of the passenger compartment fusebox (the back of the fuse panel). It is a basic micro controller (simple computer). On later models it was replaced by a more complex unit known as the Body Control Module (BCM).

Both the GEM and BCM units are programmed to your car so are not a straight swap. You can do it yourself using FORScan and loading your own cars "AsBuilt" files.

You say that you have replaced the reverse light switch on the gearbox. Do you know if the plug on the switch has one wire or does it have two ?

1 minute ago, unofix said:

GEM = General Electronic Module. It is part of the passenger compartment fusebox (the back of the fuse panel). It is a basic micro controller (simple computer). On later models it was replaced by a more complex unit known as the Body Control Module (BCM).

Both the GEM and BCM units are programmed to your car so are not a straight swap. You can do it yourself using FORScan and loading your own cars "AsBuilt" files.

You say that you have replaced the reverse light switch on the gearbox. Do you know if the plug on the switch has one wire or does it have two ?

It had two wires, the connection is a triangular kind of one with two pins

Just now, SilverMk2Ghia said:

It had two wires, the connection is a triangular kind of one with two pins

Unplug the connector and use something like a paperclip to short-out the wires in the plug. Turn on the ignition and see if the reverse lights are on.

Just now, unofix said:

Unplug the connector and use something like a paperclip to short-out the wires in the plug. Turn on the ignition and see if the reverse lights are on.

Sounds good! I'll hunt down something suitable and see what happens!