Hi, there is no power going to the unit. Checked the wire before the block connection to the light unit. The rest of the lights work on the unit only the brake light doesn't.

A wire break in the loom where it comes from the body to the tailgate?

So here's no supply to the nearside unit when the brake pedal is depressed but the offside is OK?

Work back from the n/s unit. As above the flexible connections between the body and the tailgate are a classic place for wear/tension and fatigue to cause wires to be open circuit. My Y2K Xantia estate was a s o d for that. Brake lights, reversing lights and parts of the rear light assembly all self disconnected at one time or another albeit after the car was ten years old.

Do you have a wiring diagram?

If it's a canbus system then is the CPU at fault?

Just spoken to the garage where it failed its mot and they reckon it's a can bus problem. And it will cost an arm and a leg to sort. Any ideas, before I spend endless amounts on it??

Thanks. That sound like a better option. No warning lights on so this could be a solution. Thanks for the advice. Is it easy to do this? Not the most electrical minded person but will gibe anything a go

Great. Thanks. This won't make the other lights blown or fuses trip out wil it? Will try this and see what happens will keep you all updated.