Electrial/ Fuse issues!!

[fiats4me]

On my '75 Fiat Spider 1800cc I am having issues with power to 6 fuse holders in in fuse box! (all fuses are good)

Initial problem was while cutting the console to hold a newer style radio the cigarette lighter sparked. The result was cig lighter, interior light, clock, 2 fuse holders failed to work. Also the water temp. automatically hits overheat even when ice cold.
I did locate a 3 amp (inline?) fuse under dash near steering wheel, will replace and update status.

All lights, directional, other gauges work, radiator cooling fan works.

Not sure what to do to correct situation. Suggestions??

[So Cal Mark]

sounds like you melted a wire that is now shorted to ground

[spider2081]

I think you have at least 2 separate problems.
I think your cigar lighter, clock and courtesy light are on a in-line fuse behind the fuse panel. This fuse might have blown when you saw the spark. This fuse is not in the fuse panel itself. It is located somewhere behind the fuse panel and instrument cluster.

The water temperature gauge needs to have a low value of resistance on the sender wire for the needle to peg in the over temp area. However the gauge does have a power wire, a dash light wire, and a ground wire that connect to the gauge. the ground connects to the ground spider behind the ignition switch. Its possible a ground was dislodged when the center console was removed. I don't know what the gauge would do if it has power, and sender connected and no ground connected but I wouldd look at the ground terminal tosee if you see any disconnected.

[fiats4me]

With ignition off, I replaced one relay switch and lost power to 4 fuses but have power to all items. How can this happen? and if a ground wire possibly melted how do I test for this to resolve issues? tx for any and all help. Pat
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[spider2081]

If you burned a wire you would most likely have seen smoke and you should smell that something has burned.

Th inline fuse for the cigar lighter should be an 8 amp fuse. Maybe you changed the wrong fuse or you put in too low a value. Did you recheck it after you changed it??

With the ignition switch off (key out of switch) I think you will have power on only one fuse in the fuse panel. Then with the switch on a couple more. I think 4 of the fuses are for your headlights they should have voltage with ignition switch on and headlight switch on.

Are you using a test light to check for power??

[fiats4me]

Ok getting some helpful answers - TX
Located the inline fuse - behind fuse box- that is blowing 8 amp fuses. I'm not sure as to why still. Will trace (taking apart instrument panel) this coming weekend possibly to emergency flashers.

Yes on using light tester to test both sides of fuse holder. Maybe fuse box not properly grounded or bad wire behind connector of fuse box.

[spider2081]

It is easy to knock the power wire off the cigar lighter or courtesy light when installing radio in center console. I would pull the radio and look in there with inspection mirror.

[fiats4me]

All issues resolved with the exception the temp gauge still goes to overheat when key is on. Replaced with new gauge - same happens. (everything else works).

[spider2081]

The green wire on the back of the gauge itself is the wire from the temperature sender in the engine head. Disconnect this wire and if the gauge then goes to the lowest temp on the gauge. If it does some how the wire between the sender and the gauge got shorted to ground.
If that does not change the meter pegging in the red. ground the meter case to the cars metal body and see what happens.