I know this is digging up a pretty old thread (and might not even be watching it any more), but did you ever end up figuring out what the issue was??
Exact same thing has happened to me (S2 RS4), I installed a new head unit and replaced the 2 bulbs that light up the auto shifter (they were blown) while I had all the centre console out.
When I put it all back together the cluster guages, and a bunch of other lights (including the shifter) aren't working now.
Checked all the fuses in the cabin and in the engine bay (just in case). Didn't try the plugs behind the cluster yet, but dont really see how they could have come loose.
I had the battery disconnected the whole time, so I don't think I have blown anything, but I suppose it is possible.
Or anyone else got any ideas?
