headlight/head unit problem

[ian`s 2]

This is a strange problem as soon as i put my headlights on my head unit goes off but if i turn the headlight stalk back 1 turn so the lights are up but not lit the head unit stops on .

I have just installed new wires for the head unit as the previous owner had chopped the wiring to pieces i wired it as follows,

12v feed from batt with a 20amp fuse,
switched live from the cig lighter,
and earthed to chassis,

Have i got to put a bigger fuse in the cig lighter to cope with the extra drain from the head unit?

[Lee8ballauto]

Is your feed from cig lighter coming off the light on it?

[shinny]

Have i got to put a bigger fuse in the cig lighter to cope with the extra drain from the head unit?

No - the radios and lighter come off same fuse anyway (it's the RAD & CIG fuse). BTW if you'd blown the fuse then your clock wouldn't work either, and if you've not blown the fuse then the fuse is not the problem.

the head unit stops on

Uh, what? I don't understand what you meant there

Does your head unit turn on when the your switch on to IGN? Clearly something is wired wrong but it seams rather odd that turning one thing on turns something else off.

[RST]

I almost thought you had a wire crossed before, except for the stays on bit.

2 questions:

Did you "sound out" the wires with a multimeter? By this did you find switched and permanent lives with a meter or just trial and error?
Is it an old head unit or a new one?
Is it a new head unit or old one -there's wiring diagrams provided with new ones, of not and your sure the old one is good make sure you google the diagrams for the old one and leads me onto the first question about checking wires

I've spent ages trying to get old head units to work to no avail and ended up buying new. Even a stock one had me confused once with absolutelty no traceable ground whatsoever.

[ian`s 2]

Fixed it it was the battery goin flat I've charged it up and all is well now

I thought I was going mad because I checked every wire at least 10 times.

[shinny]

Fixed it it was the battery goin flat I've charged it up and all is well now

I thought I was going mad because I checked every wire at least 10 times.

Oh - you switched on your headlights and the stereo went into it's low battery cut-off (11V normally). That does explain it rather nicely