Electrical head scratcher
 

Hi to all from the UK

Got myself a little 2000 plate Demio to use as a little run around and work commuter. Absolutely perfect for that purpose and has been doing me proud in providing nice and cheap commuting.

Anyway tried to wire in a new head unit the other day. Got it powered up ok and then stuff started to get weird. When measuring the voltage for the yellow, power cable to the head unit I was only getting 5.8v. Voltage at the red ignition cable was fine at 15v when the car was running. I also noted that the clock time reset. Subsequently the clock, interior light don't work and the immobiliser doesn't seem to engage. Everything else seems fine. Fuses on the drivers side are all fine so I'm kind of completely confused at the moment.

Any suggestions please, I need my sounds!!!