Can anyone help please. I've had the stop/taillight fault come up, all bulbs are sound. The lights work for a nano second when turned on initially but then go out! I've taken it to one garage and they can't find the problem.

I'm hoping it's just a case of replacing the bulb housing unit......but thought I'd ask here first!

I would start be making sure the contacts are clean and that all the earths are good.

...Can anyone help please. I've had the stop/taillight fault come up, all bulbs are sound. The lights work for a nano second when turned on initially but then go out! ...

Well, what that sounds like is a short (and it sounds like you are looking, primarily, for an open circuit).

When the light initially turns on, there is a 'short circuit detection' function, and if the module detects that something is shorted, it turns the output off to prevent damage (there ought to be a fault code associated with this, although whether that takes you further than just knowing there is a fault is another matter).

The most likely is a short to ground (there is a lot of ground around to short to, partic if the wiring insulation has worn through somewhere, or connections have been remade, and a single thread of copper wire has been left 'floating around'), but a short to somewhere else, eg, battery, is also possible.

I'd look around the wiring and the connectors at the lighting unit end first (because they are easier), but it could also be at the module end. Using a DVM might also help you find the short, assuming that is really what is going on.

Edit: probably way closer to a millisecond than a nanosecond, but I assume that is closer to hyperbole than a measurement with a oscilloscope. Arguably.

All solved, just replaced bulb housing unit.

Glad your sorted, electrical faults can be a bigger to find