A4 Reverse lamp stays on

[charliecharles]

Hi,

The reverse lamp switches on and off whilst the car is switched off and locked! The light comes on about 30 seconds after the car is locked and can stay on from a few minutes to over an hour.

The DIS informs me the rear left fog lamp is defective - there is no rear left fog lamp, it is a blank plate - i have checked the light cluster - no corrosion, and the loom/connection to the rear lamps - no corrosion or break in the wires.

Any suggestions would be appreciated, next on my list was checking fuses (this has been suggested on other posts).

Many thanks

Chris

[kite]

I have had this.
Clean all bulb connections in both rear light clusters

using tapatalk from my phone

[charliecharles]

I have replaced all of the rear lamps, checked connections and wires (local)- all look good. Left reverse lamp still switches on when car switched off (not in reverse!).

I have checked the fuse box, it looks like water is leaking in above the fuse box, fuse blades have been cleaned (non were melted), this has still not solved the problem.

I have temporarily removed the offending lamp until the source can be found.

Can anyone suggest where the water is coming in? Is there a channel/drain which may be blocked, if so how would i get to it. Are there any ECMs located in this area?

Another possbility is that it is a poor earth connection - does anyone know the location of the earthing points for this circuit?

Many thanks,

Chris

[kite]

Check the bulkhead drains, 1 under the battery and another under the brake servo.
Also the seal on the underside of the ECU box can perish.

using tapatalk from my phone

[charliecharles]

Battery removed and the two drains cleared. There was a pool of water, with an obvious water mark higher up. Struggling to get at the ECU box currently as the wiper arms are ceased on - not allowing me to remove the plastic scuttle at the bottom of the windscreen - i have left these to soak in WD40 overnight!

Hopefully this has rectified the cause of the problem, but i'm concerned one of the control modules may have failed??

Thanks

Chris

[kite]

Check the front passenger footwell for damp.

using tapatalk from my phone

[charliecharles]

Front passenger footwell dry. Drivers footwell now nearly dry! Still having reversing light issues, now both come on intermittantly when car locked (and fuse removed for this circuit!)! Also noticed windscreen wipers move very slowly.

[pauldazzle]

Just replaced my reverse light switch as I had a similar problem with reverse lights coming on randomly. Solved the problem.