Rear stop light issue

Hi guys,

I have a 2004 T3 that i have had for about 3 months now, it was bought with 106,000 miles on it and i have added about another 10000 in the time i have had it.
It has been totally reliable and that's a big ask as i'm using it as a taxi so it gets a bit of a hammering.

A couple of days ago i noticed the driver side stop light was not working, being LED i knew it was not going to be a simple fix so i checked the fuses, wiring, Printed circuit board and all was good, there was/is 12 volts running to the LED bulb unit and when the ignition is on you can see the bulb is very faint when the brake pedal is pressed.
I instantly think the unit is faulty, after all i have 12 volts right up to the bulbs, so i order a brand new unit and am waiting for it to arrive.
Tonight i am driving, my partner is behind me in her car and when we get home she tells me the drivers side light is now working but the passenger side is not .
I strip out the light unit and the symptoms are identical as the drivers side one, 12 volts right the way through to where the wire goes into the LED bulb housing, with the ignition on and brake pedal pressed it is glowing at about 1/2 brightness i am now at a total loss as to what the problem is.

Can anyone help with any ideas please, i am desperate as the car has an inspection in 2 days and i need this issues totally resolved

Thank

 

I ended up replacing the lamp assembly.
My readings were the same as yours, I tried different earth points, even tried putting a new earth wire in, all to no avail.
Behind the led bulbs must be another printed circuit board that you cannot get at, this must be the issue point