Fuse #1

[spidernut]

Here's one for the books: Fiat Spider with electrical issues. Car #2 decided that when it warms up to full operating temperature, it will randomly blow the #1 fuse and I lose all the gauges and turn signals, etc. I spent part of the day trying to track down a short...nothing so far. I checked voltage from the alternator: 14.5 volts. Ideas?

[TX82FIAT]

yep, you are on the right track. You most likely have a hot to ground situation (short) someplace. I hope that is not the case. I had to remove the dash and trace the circuit. what I found was at some point.. maybe even at the factory. a copper wire was pushed through the wire harness to secure it to the metal rail under the dash. After years of rubbing part of the wire casing had worn and the wire grounded out.

[spider2081]

My wire diagrams are for a 80-81 but I think it is basically the same. Fuse 1 also has the back up lights on it. Not sure if automatic transmission cars have problems with the switch wires like manual transmissions do. Also your seat belt switch wires are on fuse 1.
Did your signal lights work well before the fuse blew.

[spidernut]

100% of all the electronic systems work and work correctly.

- Turn signals: OK
- Emergency flashers: OK
- Gauges: OK
- Warning lights: OK
- Back up lights: OK
- etc.

This car is a manual transmission - what's the issue with the manual transmission back-up lights? Come to think of it, I didn't have this problem until I hooked up the reverse light switch - which works properly by the way.

Ideas?

[spider2081]

It is not uncommon for the wires to break off the back up light switch at the rear of the switch and short to ground. This blows the fuse. If you just hooked up the switch did you look at the wires at the back of the switch to see their condition??? IF not I would look there first. The two wires go up along the transmission then forward behind the radio panel and join the main bundle above the radio panel. They then follow the main bundle one to fuse 1 and the other to the rear of the car.
If the wires on the back-up switch look good I would disconnect the switch and see if the fuse stops blowing.
If this isolates the problem to that circuit I would start checking things in the trunk. Actually right at the Printed circuit boards in the tail lights. then the wire bundle that connects the right tail light assembly to the left.

hope this helps