Brake Light Failure on one side - Bulb and Fuse are OK

[ck_uk]

Hi all

Audi A4 B6 Avant 2003

Getting a series of warning messages, when switching on ignition, bit concerned as MOT is looming..

Rear Left Brake
Rear Parking Light
Rear Left Fog

In actuality, only the brake light isn't working on that side (works on RHS)

The Parking light and Fog light are ok

I changed the bulb for a new one - same problem.

Checked the brake light fuse - ok (there is one 10A fuse for both brake lights)

Not sure what else to check, I've had the cluster out to change the bulb and the connections all look ok, no corrosion etc.

Can anyone suggest how to progress with fault finding?

[Crasher]

Always the left! Check the Earth pin in the plug and bulb holder, it is probably burnt out which means new plug, repair wire and bulb holder.

[Lizard821000]

I’m having a similar issue but on the right side , rear right light warning , it’s intermittent but mostly on as a warning ⚠️

I bought a known working used cluster and swopped them around and actually made it worse and got faults popping up for the left side fog 😂

So put the old one back in , cleaned it all up, checked it over and checked the plug pins and bulb seats too, all looks well but the right side stop light still isn’t working and have the intermittent warning ⚠️ for it

If I play about with the plug 🔌 I can get the fault to sometimes disappear leading me to believe it’s just a bad contact in the plug 🔌 but how do I open it up to check? Looks sealed

Anything I can check too? As a new cluster ain’t cheap and might not even be the problem