Copied from email, for future searches:I have a 96 Cabrio that has a different year tranny (large plug Reverse Switch), so I wired it to work as per the directions on a VW site : this was a couple of years ago. Today i notice the lights were on again so i thought maybe wire came loose off the switch. They were intact, so i started to look for possible cause. Attached to the wires is another cannon plug that goes into the tranny about three inches behind the reverse light switch, It was dangling with half of the conector that should be in the tranny, I am assuming it has something to do with reverse since it is broke and I have the light always on issue. What is it called? Or is it simply a bad reverse switch.
Originally Posted by Broke via emailIt sounds like you are describing the VSS, the speedo. Does your speedo work?
The MK3 uses an electronic Vehicle Speed Sensor in place of a mechanical speedo cable.
The VSS has 3 wires that attach to it via a plug... just like the reverse switch, but with an extra wire.
The VSS shouldn't affect the reverse switch at all, so if the reverse lights are on, the switch is connecting the 2 wires and completing the circuit. The big reverse switch is known to fail, so it may be stuck on.
First test... pull the wiring from the reverse switch. If the lights go out, the switch is the problem.
If they stay on even after pulling the wires, then you have a short somewhere along the wiring to the reverse lights.
I'm assuming they will go out when you pull the 2 wires from the switch. If so, pull the switch, and check to see if the pins are still springy. If not, the switch is done and should be replaced.
Check terminals #2 and #8 on the switch with a multimeter, checking for continuity between the 2 terminals. There should only be continuity when the switch pin is pressed in, simulating it being in reverse gear. When the pin is released, the lights should go out.