Superunknown

I had the EXACT same symptoms! I too couldnt lock the doors using the key either. Like you said it just seems that turning the key just activates the central locking but as there is no power = no doors locking. I tried cleaning the battery terminals but had the problem again. I took off the ground cable, soaked it in wd-40, wire brushed it and put it back on. So far no problems! When i untwisted the cable i noticed alot of green stuff coating the cables, which i guess causes the electical resistence.

LoFi

I read this thread last night and would you believe it - today absolutely the same thing happened. No power at all. No interior lights, nothing. Then it just worked. Then it didn't. I have just removed the ground strap and cleaned and rubbed sown the ends. Not sure if it will be fixed.

I will try seeing if there is a voltage drop and/or resistance in the ground strap and then try the soaking in wd40 and cleaning if necessary.

Very odd though.

Piers