1982 Mondial QV UK Version, changed battery and now problems

Hi all you Ferrari Mondial experts, I have a 1982 Mondial QV UK version Right Hand drive. So I changed my battery on the Mondial this week and the first thing I noticed was I have lost my instrument lights. Checked fuses and all ok, cant work it out, I then realised I lost my front and rear fog lights, fuses checked, all ok, then my lights wouldn't pop down, fuse checked, blown, replaced fuse, blew as I was replacing it, replaced it again, blew straight away.
the only thing I can think is that I may have caught something whilst changing the battery but what? Everything appears to be ok and I have no idea where to start

 

I don't have any experience with your car, but there is a general requirement when changing a battery on a modern car that has several computer modules. Before you disconnent the battery, you need to add a trickle charger to the electrical system. Failure to do so very likely will result in a memory loss in some of the computer modules. Although you might be able to reset some of them; others might require taking the car to dealer for a reset.

 

I'm not sure a Mondial qualifies !

Could the battery be reversed by accident ?

 

Reverse polarity would immediately blow-up the alternator rectifier bridge. Unless you've seen a big spark on the battery post and heard a loud "pop" from the alternator, I would tend to consider your polarity is correct. If the the clock is operating, this would also suggest the battery is more or less properly connected.

 

The clue is that your light fuse is melting. That indicates an over-current situation that is 99 times out of 100 due to an electrical short circuit. In other words, you have a positive wire that is in contact with ground (any metal chassis point), most likely either on or near the battery since that is where you were working.