C5 4.2 automatic reverse light switch position

[martinhnilsson]

Hi

My reverse light doesn't work so I thought I would start by checking if the switch is ok but haven't been able to find where it is located.
Anyone know where the reverse light switch is?

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[chris86vw]

The switch is built into the multi function switch on the transmission. It is not a separate part the whole switch assembly must be replaced. In theory you can test it but it isn't as simple as the manuals where you could just pull it out and press the detent and check to see if it opens/closes the circuit.

[Gogeees]

I watched Phil at Audis4parts.com install a new switch and wire it to the ECU while swapping in a 6 speed in my S6. I believe the switch is on the transmission, and is actuated by the shit linkage? It looked pretty hard to get to and he used a very long ratchet extension to get to it from underneath the car while on a lift. The wiring then came up behind the firewall by the master cylinder, out through the firewall and into the ECU.

This video may help.

https://www.youtube.com/watch?v=tsUOed1AEes

Good luck!

Sorry ignore didnt see auto.

[Gogeees]

Check fuse 31, it controls the power to the reverse lights.

[martinhnilsson]

Thanks everyone

Fuse 31 looks good.

Any other way of diagnosing what's wrong?

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[chris86vw]

Thanks everyone

Fuse 31 looks good.

Any other way of diagnosing what's wrong?

With VCDS you can go into the transmission and check the readouts of the multi function switch in measuring blocks. But reverse to the modules and reverse to the lights are two different things, just would be a start to see if there are other issues with the MFS.


There is basically a reverse light switch in the MFS that operates on its own for the lights. Blue/red wire to pin 8 on the switch goes directly to the lights (well through a few connectors). The power from fuse 31 is black/blue coming in on pin 7.

[martinhnilsson]

With VCDS you can go into the transmission and check the readouts of the multi function switch in measuring blocks. But reverse to the modules and reverse to the lights are two different things, just would be a start to see if there are other issues with the MFS.


There is basically a reverse light switch in the MFS that operates on its own for the lights. Blue/red wire to pin 8 on the switch goes directly to the lights (well through a few connectors). The power from fuse 31 is black/blue coming in on pin 7.

Thanks! Great in-depth knowledge:)

As I have the gearbox out at the moment I put a multimeter between pin 7 and 8 and checked for signal. Good signal when in reverse and no signal in any other gear. So thats working correctly.

Next step I guess is checking wires back to the lights?:(

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