2010 LV Focus LED Stop/Tail

[danobolto]

Hi Guys,
New to the forum.
I have a 2010 LV Focus Zetec, Being the zetec the rear light cluster lens is clear and therefore it uses coloured variants of a stop/tail light bulb. Due to the extreme rarity of the type of bulb used (European version of standard P21/5 with weird pin offsets which I was told by my dealer is discontinued) And the fact that the incandescent lamps do not produce very vibrant colour I have decided to attempt to opt for a LED Version. It arrived yesterday and I discovered an issue when I installed it. The LED bulb works by offering half power to the LED's when the parking light contact is giving 12v and full power when the brake light contact is given 12V and I can verify this as working on the workbench with a 12v battery and 3 jumper leads. The problem is in the car. the bulb will only work when it is only in contact with the either the stop or parker light contact not both at the same time. Regardless of whether the brake lights or parker lights should both be switched on or only one of the two. The bulb will immediately turn of when it is contact with both contacts in the bulb assembly. The bulbs are canbus free bulbs with built in resistors if this should mean anything. Though considering the LV doesnt seem to have any kind of canbus bulb out warnings I dont think it does.

Has anyone tried to retrofit similar LED bulbs and faced this issue?

Cheers