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My gauge dimmer bench-tests perfectly and is connected but does nothing. If I remove it, the gauge illumination stays on full (when headlights switched on).

I have no idea where to start troubleshooting this.

The only non-factory things I can see is that the console illumination dimmer has a wire tapped into it that disappears above the speedo.
And -likely unrelated - the parking brake and brake warning lamps appear to have been replaced and are (poorly) connected to a pink + 2 grey wires and a black/white and 2 grey wires:


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Bearing in mind I have never specifically worked on Pantera wiring: Is the dimmer a coil rheostat? These can test OK when you use low power test like from a multimeter but when you put them on load, they can break down. Is it connected the right way around?

I would fix those two extra connections properly to remove them from the equation, and also trace the extra wire coming off the dimmer as I expect that is a bodge. Also, check the resistance in all the grounds.

Chasing wigglies like this is always a headache.

+1 on the load/no load test.

Mine was like this and it was the switch itself. I actually removed it entirely.

You need to realize that both the Italians and the Brits have this long standing belief in witchcraft. Unfortunately it sometimes appears in their electronics.

They like to blame each other with doesn't help fix the situation at all.

You just want it to work. They just want the other one to be blamed because neither has a solution.

Typical Euro nonsense.

Jim, unfortunately the Pantera wiring is a mixture of prefabricated wiring looms from '60s British/Lucas, Italian /Fiamm and German Capri/Bosch. Thats why as an example if you dig into your cars wiring, you'll find about 6 extra feet of taped-up wire bundle underneath the front hood cross support. A couple are unconnected on both ends. And that does not include any amateur connections made with house wire connectors or simple twist-together. These are often found sort-of connecting a stereo & speakers, which was not factory-offered in the US.

There are four (4) different factory schematics available by date of publication. Try to find one that's closest to your car's build date, and annotate your schematic to fit your car. None will be exact. Trace out all the amateur 'fixes' that usually don't- like your dimmer rheostat. The entire dash & console are fiberglas so all the meters, switches etc need good grounds. All cabin grounds eventually terminate at a double-end stud up behind the speedo. The other end of that stud penetrates the firewall and is the front trunk battery ground. There is usually corrosion underneath the nut under the dash. Tip: when something doesn't work, FIRST check its ground. A good VOM is the Pantera owners best friend.

Most factory dimmers can be fixed on your kitchen table. On the backside are a pair of small rectangular steel bar ends that protrude slightly from the case. Tin the ends very well with a good soldering iron, and connect a short insulated jumper wire (any gauge) across the bars. Inside the dimmer is a hair-fine wire that, for reasons that escape me, carries the entire power load for the otherwise well- made dimmer. This jumper only bypasses the fine wire that usually breaks from vibration over time. The Pantera is rather stiffly sprung which doesn't help. Good luck.

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