One Brake Light Dimmer than other

[Focus2112]

G'Day

I have a 2006 ford focus hatch 2.0L (auto). It has approximately 210 000 KM's so its no spring chicken. It has an odd problem of having the drivers side brake light always being dimmer then then passengers side. You can tell its still working only at night only thats how dim it is. I changed the bulbs, ran a diagnostic but no luck. Can some one suggest any ways to rectify? I was thinking..1) perhaps a ground issue so cut the ground and re-ground it some where else? 2) daisy chain or link it to the working brake light that isnt dim (but unsure if that will dim that out too?) Or 3 change the socket for the brake light globe?

Any ideas?
Cheers

[GTLEGEND]

I had the same problem with my 2006 LS Focus on the drivers side. Had to remove the tail light (3 torx screws) and found that the connector to the brake light earth pin was slightly corroded and opened. Cleaned it up and closed up the gap of the earth wire, all good. If its not that on yours its an issue with the earth somewhere.

[GTLEGEND]

If what I suggested does not work, you may also need to replace the brake light globe socket itself, part number XS4113K370CD. Can help get one if need be.