Ghosts in the machine

Hullo all

I have a bizarre electrical gremlin in my 300GD(463) whereby if I have my lights on, after a while of driving the preglow indicator will flash intermittantly on and off, sometimes flickering and sometimes on constantly for up to 5 secs. When this happens there seems to be a drain on the whole system and the lights inside and out all go dimmer. Now I think there may be a cabling issue with the light switch itself, which I am intending to have a look at.

Also my passenger side window keeps blowing its fuse, if I replace the fuse and use the switch it works fine with the ignition off, but when I switch on the ignition and the G is running the fuse blows straight away, very strange....

I was just wondering if anyone has come across these problems before I dig in and start tearing my G's electrics apart. Many thanks.

Adrian.