Evening guys,

im new to this so bare with me haha, I have a mk3.5 focus zetec and I’ve swapped the headliner and according wiring loom for one off of a focus ST250 purely because it’s black with all the pillar trims and i got a good deal, the loom plugs into all the right places such as into the left and right front pillars and into the passenger fuse box. But the issue is now none of the interior lights work, have I missed something or is there something I need to get for it? The guy I got it from said it would fit which it does but now the lights don’t work as well as the lights in the sun visor mirrors. If anyone has any suggestions let me know, thankyou!

On The Focus MK3/MK3.5 Ford used interior lights with old fashioned bulbs for the lower spec. vehicles and interior lights with integrated SMD LED lights for the higher spec. vehicles. Apart from the different interior lights itself the wiring is also different.

I suspect that being a Zetec (which is considered to be low spec.) your car has interior lights with old fashioned bulbs while the ST250 has interior lights with integrated SMD LED lights. If this is true the wiring harness that came with the headliner is not compatible with your car. In this case you either have to change the wiring harness or modify the wiring harness that came with the headliner to match the original wiring harness.