Running lights, tail lights

[essenz]

Ugh, I guess it was only a matter of time till electrical gremlins. Trying to sort this out.

First, when my headlights are on, I assume : a) the side marker lights should be on, and b) the rear tail lights (red) should be on, correct?

Then when I press on the brakes, and additional bulbs lights up (red).

Currently this is not happening on my '84. Turn signals work and brake light works, but thats it. No side marker lights or tail light when the headlights are on.

Going through the notes of previous owner, in 2004 there was a tail light hack/fix - but no details. So not sure if this is a known issue and they did a half ass repair.

Additionally, in the fusebox there was a wire connecting the bottom of two of the fuses. I think that was the hack? Unfortunately, I removed that wire - it may be what broke the tail lights - replacing that later today to see if it restores. There is also a splice into the red wire coming off the ignition switch - the cars runs fine without it (I added it back after I replaced my ignition switch) so I assume its related to some electrical accessory.

Lastly, my dashboard lights are no go. Rheostat does nothing, so driving at night is tough. I doubt all the bulbs are burned out, but will check that.

If any of this tail light stuff sounds familiar, let me know. Going through the electrical diagrams, but its tough because there is a moderate amount of hacking thats occurred bridging the gap is complicated

[spider2081]

I think your parking light and side lights should light when the Steering column light switch is rotated one click from the "off" position. That should light a green dash warning light that the lights are on. I didn't see if you stated the front parking lights in the bumper light properly.
When the ignition switch is in the "off" position the parking and running lights can be lit by moving the switch on the top of the steering column to the center position and/or rotating the light stalk one click from "off" Fuses 7 & 8 arethe parking light fuses.
I would join Mirafiori.com and look in their library. I think there is an owners manual for your car describing the lighting operation.
Also there is a Fiat publication "Spider 2000 Electrical Diagnostic Manual 1980-1981" you might find very helpful. Your lighting circuit is slightly different but most of the Manual applies to your car also.
Joining Mirafiori is free and you need to be a member to access their library.

[essenz]

Yes, headlights work fine. There is no dash light though. I have a blue dash light for when the high beams are on however.

One other quirk, the turn signal dash light is constantly light solid, when I engage the turn clicker it flashes. So thats bizarre.

Unfortunately I inherited a bit of an electrical hack job, reverse engineer the hacks back to factory is tough. Clearly something broke a long time ago, and was un-repairable, so they went the hack route.

Im pouring over the docs now. Was mainly curious if this was a common 90's/2000's hack.

[spider2081]

Was mainly curious if this was a common 90's/2000's hack.

It's not anything I'm familiar with.
I didn't mean to be asking about the headlights. In your front bumpers there are amber parking/signal lights. I am curious if they work as signal lights and parking lights