Strange electrical issue

petertr

Bit of a long-shot, but you never know.....

 

About a month ago, I have air con fitted to my MH - and also an inverter so that the air con works while I'm driving.

Since then, even if I turn the master light switch to "off", my lights come on "a bit" if I press the individual switches.

 

The only thing I know that was changed during the work was:

1 - Charging circuit was uprated 

2 - One of the 3 pin sockets becomes live when the inverter is running

 

Anyone suggest what the cause could be?  I've already contacted the company who did the work, and they are coming up to take a look later this month - but any suggestions would be gratefully received.