The problem seems to be the blue seimans plug on the back of the unit. I found it easier to get the unit out by first removing the stereo. The unit is held in by 2 sprung clips and you got to get your fingers behind it and give it quite a pull but it will come out. The unit is sealed so you can'y get at the solder connections to the socket (but I suspect it's the plug thats faulty) I "messed" with the plug and got it into a position that the unit would work and then ... here's the crude bit.... wedged a piece of plastic inbetween the unit and the plug then secured with tape. Not very professional but has worked for a few weeks now.
While I had the unit out I removed the for screws holding the facia plate on and cleaned out the air intake port. Be careful as the is a temp probe (well I think thats what it is) at the front of the port. Mine was covered in dust and fluff and could not be seen. Used the hoover and a cotton bud to clean.
Hope this helps.