Hi all does anyone know what the small black electric box does under the headlining that's connected to the rear sunroof motor? my sunroof motor works if I connect to a battery but not when plugged in... theres 5 wires coming out of the main plug that leads to the front of the car.. then that plug goes to the rear sunroof motor via the black box... theres 5 wires coming from the plug going into the black box but theres another 5 wires from the box going to the motor and to make things difficult the wires are diff colours to the ones coming out of the plug... can I bypass the black box and join the plug wires to the sunroof motor? if so can someone tell me what colour wire goes where cos im stuck lol i used my multimeter on the plug 5 wires and 2 show 12v the other 3 must be earths cheers

All I know is that it is a 'Rear sunroof control unit' with a circuit board inside, I have the same problem, front sunroof ok, rear sunroof not working. supply to switch ok, and like you say there a 12V supply to the black box.

Do you know about the resetting function?

Hold the switch in one direction until you hear a click/clunk (takes approx 20-30 secs), then do the same in the other direction.
My front one stopped working the other day, half-open, doing this sorted it out.

Update on Rear Sunroof... Got a secondhand Black box (Rear Sunroof control unit) from ebay. Fitted this evening and Sunroof works OK. Details of unit removed ...Webasto 60.024.03 HW3.2 SW3.3 PS19 XS5Y-1572-AB ,hope this helps.

Have had a look inside the 'black box' and there is a large black relay...'tyco V23078-C1002-A303' googled this and found that it is also used on BMW's for controlling electric windows. If the relay has packed up would imagine that sunroof would not work, as it would appear to control the sunroof motor, just like it does for the windows on a BMW.