[fredjacksonsan]

Hmmm...well it could be a short or other electrical issue; but I've heard of stuff like this being caused by odd voltage - either old battery or corroded cables - or it might be the system needs to be reset.

I would first try disconnecting the battery and holding the 2 battery connections together. This should drain all the voltage and reset everything.

While doing that, check the cables for corrosion. I once found corrosion gong back about 22cm from the battery, INside the insulation. Then make sure all the connections are tight.