Thought I just finished my indicator/hazard/dip/main lighting and I was tidying up the wiring when I came across three wires I didn't know what they were for. They were the looms original flasher relay wires which I haven't used. The battery is disconnected at this point. In identifying the three I happened to put a multimeter across an earth wire and positive wire. To my surprise I got continuity. I disconnected a headlight and put multimeter across the headlight feed and the earth, continuity again. Disconnected a indicator, same result. I thought maybe I have wired something wrong. So I reconnected the battery expecting a short, none came. Everything works okay? Am I being stupid?

Could the disconnected positive strap to the battery have been touching something that was earthed??

Switched earth systems can give this
i.e. +12V to light returns through earth wire to switch, switch goes to ground when switched

I check the strap to the battery so it wasn't touching - or I thought I did. I just don't understand. Surely if I have a short or I have connected something wrong I should get sparks, a blown fuse or even a fire!!!!!!!!!!

If the positive you tested is linked to others then you may have measured a relay coil or even several such as the ignition on relay and fuel pump relay etc.

Several of these in parallel will give a reading of almost short to earth. The only way to prove it would be to know the wiring scheme exactly and disconnect the positive at its end and prove the cabling but if it was working before and it works now you probably haven't got much to worry about providing its all fused correctly.

surely the bulbs will show continuity to ground on both sides when switched off - they only produce heat and light (a controlled short circuit) when you connect them to the battery.

so the +ve lead on your disconnected bulb holder is joined to the bulb on the other side (same supply from relay) - which is connected (via the filament) to ground?

Sorted it.

I set the multimeter up for continuity and connected it in the place of a headlight. Whilst the constant tone was droning out I started moving the loom around looking for loose connections. When that failed I started unplugging stuff. When I got to the dashing warning light display pod and pulled it continuity was broken and the tone stopped. I plugged it back in and started removing each bulb in turn. The full beam warning lamp was faulty and when pulled it out the tone stopped and I replaced it with a spare. No more problems.