Bike trailer brake lights don’t work. It’s a new light board, indicators are fine, and all the lights on the car work.

Any chance it could be something simple like a fuse or an earth connection? Any advice appreciated – 7 pin plug on the car.

Try it on another vehicle first to determine whether the fault is with the lighting board or the car electrics.

Could be, but unlikely to be an earth if the indicators are working fine and not coming on when you brake. You don’t mention the tail (side) lights – do they work? As advised you need to isolate where the problem is – though personally I just used a multimeter when I wanted to check mine.

Thanks – the side lights on the board do work, just checked.

Pretty sure it must be a problem with the car as the old lighting board developed this problem, and the new one is brand new.

In the plug and socket you will see the pins are split. Get a screw driver and gently prise them apart until the plug is a snug fit. I’ve also had the pins on the car socket push back into the housing which results in a patchy connection.

(Don’t forget, if you are looking into the plug the diagram is a mirror image as you are looking at it from ‘behind’)