I have decided that there is no point in keeping the cigarette lighter (and, for that matter, the ashtray either) on my ZG GCL 1996 (ZG is the right hand drive ZJ)
So went ahead and acquired a usb dual charger with voltage indicator, a aux power socket and another 2 port USB charger.
I removed the assemble (2 screws on top of display, 2 clamps on the bottom sides and disconnected the 3 connectors and removed the ashtray light from it socket.
I removed the ashtray and dismantled the face plate and drilled 2 big holes to accommodate the additional sockets.
Removed the cigarette lighter (this proved to be extremely difficult, you have to push, rotate, push) and replaced it with the dual usb charger with voltmeter.
I built a wire harness linking the 3 pair of terminals to the cigarette lighter socket (blade connectors in the socket worked fine).
I took the opportunity to add a wire harness linking the existing AUX with my CB Radio power feed and back to the permanent on AUX power connector (same with spade connectors).
All looked fine and I was very pleased with myself BUT
When I connected the harness to the cigarette lighter connector the embedded voltmeter in the new USB charger did not show anything although I had 12V+ by FLUKE avometer when tested in the cigarette lighter connector. Disconnected, checked again, still 12 but WITH the harness connected it was showing only 2V under power.
Scratched my head and reverted to the workshop PDF manual (has search!).
The cigarette lighter power is run through a small relay in the distribution board in the door pillar.
I pulled out the relay and, with a bit of effort, opened it. A puff of some sort of dust (rust?) dropped from the case - not good...
Checked the relay, was engaging OK but the resistance between the contacts was high, that was my voltage drop that made it 2V under load.
I could not find a replacement.
I could not reach the contact point as it was behind some moulded plastics in the relay assemble.
In the end I totally flooded the naked relay with electrical contact cleaner and actuated a few hundred times. This restored good contact when relay was engaged.
Well, these are my 2 cents, maybe it helps someone else as well.
Now to figuring out why the fan control with ATC works only on max