Red starter wire

Gotta love that wiring . . .
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GreenGrizz77
Posts: 14
Joined: Wed Mar 19, 2025 2:48 pm
Your car is a: 1975 fiat 124 spider sport 1800
Location: Foothills of the Sierra Nevadas

Red starter wire

Post by GreenGrizz77 »

Hello all it’s my weekend so I getting back into the beast in all the wiring diagrams I can find the starter should have the battery cable and then just the three that go back to the ignition lock the black brown and red. I have an extra red and both red wires run up to one of the relays. I’ve got 8 relays total in that pack in the drivers side engine bay and not sure what most of them do as I can’t find a diagram that includes them. I’m taking all of my smog equipment out and planning on eliminating any relays I don’t need.

So I guess my question is does anyone know why I would have 2 red wires on my starter and should I run the red that is supposed to be there back to the ignition rather than the relay?
-Dalton & Gizmo
GreenGrizz77
Posts: 14
Joined: Wed Mar 19, 2025 2:48 pm
Your car is a: 1975 fiat 124 spider sport 1800
Location: Foothills of the Sierra Nevadas

Re: Red starter wire

Post by GreenGrizz77 »

The relay is a 90050 12v 5 prong if that helps
-Dalton & Gizmo
18Fiatsandcounting
Posts: 3871
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: Red starter wire

Post by 18Fiatsandcounting »

I'm guessing someone added that second red wire, as the stock starter motor should have only the thick red, brown, and black wires as you noted. And the beefy cable to the battery. The stock red wire operates the solenoid on the starter, so it's energized when the ignition switch is turned to the start position (but not energized in the run position).

Perhaps a relay was added to drive the fuel pump, if you have an electric one?

-Bryan
GreenGrizz77
Posts: 14
Joined: Wed Mar 19, 2025 2:48 pm
Your car is a: 1975 fiat 124 spider sport 1800
Location: Foothills of the Sierra Nevadas

Re: Red starter wire

Post by GreenGrizz77 »

I don’t believe it’s for a fuel pump I has it’s original one the PO installed an ac but the relays look just as old as the car except for the extra one for the ac that was wired in strange I wish I could post pics on here
-Dalton & Gizmo
GreenGrizz77
Posts: 14
Joined: Wed Mar 19, 2025 2:48 pm
Your car is a: 1975 fiat 124 spider sport 1800
Location: Foothills of the Sierra Nevadas

Re: Red starter wire

Post by GreenGrizz77 »

I should’ve added that both lead into the relay and 4 thinner gauge wires lead out 2 white with black stripe 1 blue with yellow stripe and 1 blue with red stripe
-Dalton & Gizmo
spider2081
Patron 2024
Patron 2024
Posts: 3030
Joined: Fri Jan 27, 2006 11:45 pm
Your car is a: 1981 Spider 2000
Location: Wallingford,CT

Re: Red starter wire

Post by spider2081 »

then just the three that go back to the ignition lock the black brown and red.
I think the brown wire from the starter solenoid battery cable stud feeds "hot all the time power" to the ignition switch terminal 30. The black wire on the same battery post connects the alternator to the battery and the red wire with the push female spade connector activates the starter solenoid when the ignition switch is in the "start" position.
Are you saying there are 2 additional red wires with ring terminals on the battery + stud of the starter solenoid? Do these red wires look factory original?
I think there is a second black wire on the alternators output terminal that also feed "hot all the time" power to the ignition switch terminal 30/1

My last question, with the drivers door open on the cars door jam there is a white plastic tag. This tag shows the cars build date. What is that date?
GreenGrizz77
Posts: 14
Joined: Wed Mar 19, 2025 2:48 pm
Your car is a: 1975 fiat 124 spider sport 1800
Location: Foothills of the Sierra Nevadas

Re: Red starter wire

Post by GreenGrizz77 »

No there are 2 red wires total one is connected in with the brown wire and the other is the one with the female connector and they both lead to the same relay while the brown and black run to the firewall It’s all old but the ends look original or done by first owner but the wires have been cut and “fixed” and you can tell where there’s some newer wire

And I will get that date later for sure but if memory serves me right I think it was March of 75
-Dalton & Gizmo
GreenGrizz77
Posts: 14
Joined: Wed Mar 19, 2025 2:48 pm
Your car is a: 1975 fiat 124 spider sport 1800
Location: Foothills of the Sierra Nevadas

Re: Red starter wire

Post by GreenGrizz77 »

01*75 is the stamp so I was wrong she’s a January baby. Also side note I know she’s a cs1 but after taking the dash out I’ve got a heater core with bs1 written on it so I guess they had a few of those left over in 75 still
-Dalton & Gizmo
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