BMW E46 3 Series Rear Tail Light Bulb Warning Earth Issue Fix.
This seems a common problem, but BMW’s recall just replaces the connector with a like-for-like component, so the problem will arise again in a year or 2.
Other sites advised earthing directly to the unit, by-passing the connector, so this is how I did it.
The tab to attach the earth to, is the one nearest to the main connector and the cable-tidy clip. If you follow it round the light cluster it is one continual bar that connects to the metal body on all the bulbs – circled here:
The spade connectors you’ll need are Blue 4.8mm female not the larger 6.3mm. The cable I used to extend the sorter lead is 32/0.2 un-tinned copper, brown.
On the near-side light cluster, I had enough excess length on the cable, so I cut the current earth cable (as close to the connector as possible), stripped it and then cut it back until the copper wire was good, with no black or green discolouration – then put on the 4.8mm blue spade connector and fixed it straight to the earth on the light cluster as shown here:
On the off-side, there was not enough length on the cable by the time I had stripped back the bad copper cable so I extended with a blue butt connector and approx. 10cms of brown 32/0.2 un-tinned copper cable:
All fixed and I’ve had no issues for the last 3 months.
Hope this is of help to you.