Hi all

I have a Polo 2f that didn't originally have a cigarette lighter. I had one retrofitted a few years ago, I believe spliced into the factory loom. The spliced wires use the OEM 3 pin plug and has power, ground and illumination. The lighter socket itself is out of another Polo.

On Friday it conked out. It works intermittently - sometimes giving power or lighting up but not both.

• I checked the voltage at the plug and there's around 12V at the illumination and power pins.

• I checked the resistance from the outside of the socket to the door pin, and I'm getting 400 Ohms.

• When I switch the headlights on, and attach a wire from the outside of the socket to ground, it lights up

I think I have a ground fault? I've got a replacement socket on order. If that doesn't fix it I'll investigate the 3 pin plug.

So:

• What should the resistance from the ground pin of the plug be to earth? (Less than 1 ohm?)

• If there is a ground fault, where does that section of loom have it's earth point?

Cheers

Check this earth point first.

Sure I will do. It looks like quite a few earths end up there and could be bad.

But - in my case it's further up the chain. That section of factory loom is for the radio power, fog light switch, rear window and cig lighter. The fog light switch seems to have a decent earth. So it's either the lighter than has a bad earth, the socket, or the wire splicing it into the loom.

This section of loom will earth somewhere nearby. If needed I could earth the lighter at this point. Would you know where it is?

I'm afraid i don't. I had an earth loss at the instrument cluster once and i found the main dash loom bunch very hard to see at all. I cut the wire and earthed it locally, as i concluded that the only way to find the actual fault would be to remove the dash totally. You can only get so far by removing the knee pockets and laying on your back in the footwell.