Totally baffled

With so many wires running in close proximity of each other in caravans and motorhomes it could be an induced voltage from other live wires running alongside the ones supplying your TV power socket?

peedee

Does the "TV fuse" supply other sockets, and are there other things plugged into them? Another device could be supplying the voltage you see.

Thanks for suggestions, I'm open to any theories. No, nothing else plugged in elsewhere in the circuit. I'm also doubtful that an induced DC could be generated to this voltage in the loom or other wiring but there again I'm no auto electrician. 

As previously stated it could have been induced from another cct, caravan wiring is so badly designed that you get all kinds of induced voltages on the LV circuits. If you measure the current in these circuits they usually read 0A indicating it is an induced voltage.

Alternatively the antenna amplifier is active and can induce a spurious voltage on the 12v rail.

The other option is that you have a circuit fault on the 12v cct. The fuse was blown and this should not really happen on a TV. The 12v cigar lighters are really poor and can go short cct., I have had them fail.

Cheers phishy, what I'll do is disconnect 230v from the van and check the 12v system again. I'd be very suprised if without AC running through the veins of the van there is any induced voltage. I'm still intrigued and would like to get to the bottom of this though.