I have an intermitent electrical problem with my Fiat. The temperature
gauge leaps about if I brake, use indicators, turn on lights etc. This
only happens in very hot weather or after I've topped up the rad. It stops
after a hundred or so miles (or until the water has boiled back off
again). My garage said it was a problem with a low battery causing the
alternator to spike and they've fixed it by replacing the battery but it's
doing it again and has done this since I got it (2 years ago) and surely
the battery would boil if this was happening. Help, any ideas would be
great as my otherwise fantastic car is a nightmare to use when the dial
leaps about, it's distracting if nothing else.
Thank you