1975 Mystery Electrical Component?

[707kevin]

What is this?
I can't find it on any wiring diagram. Has one +12 when key is on.
It was located under my heater box. The wiring runs into the main harness, I did not see another connector.



The wiring looks factory original

[TX82FIAT]

Not original part. Looks like someone rewired your ignition switch. A friend had a TR6 in high school that we worked on in the early 80's and that looked familiar so I goggled it. What you are looking at is a Smiths 'Logic Control Box' starter ignition interlock for British cars: Triumph TR250/TR6, Lotus Elite, Jensen Healey, Jaguar XJ6 4.2 Series II, XJ12 5.3.

[707kevin]

What the... Glad someone recognized it.
What exactly is its intended purpose?

I'll trace the wires back further and see about removing it. It does not affect the operation of the car while unplugged.

All of the seatbelt warning switches, courtesy light wiring, 25000mile timer, cat temp and all of that have been removed. by the previous jerk. I mean owner.

I don't have smog check, so I'm OK with removing smog equipment and cleaning up. The amount of loose cut wires under the dash is astounding though. About 4 hours into it I realized that he was cutting and moving wires under the assumption that it was +switched, not - switched. Dork.

I removed a mystery switch inside the glove box that did nothing. Also trying to figure out what the extra on-off-on switch was installed in the center console for.

I'm now working functional hazards. I fixed the turn signal circuit last night (previous idiot, I mean owner cut the grey wire from hazard switch, so turn signal flasher never energized.)

Next will be returning the electric fuel pump to it's original wiring. I guess testing a relay is too hard for some people, and they would rather run new wires??? arg...

At least I enjoy the work! I've only got 50 miles on the car since I bought it.

[bradartigue]

The wiring you are showing is original ignition switch wiring; the interconnect device though is unique. While mid 70's cars in some cases had weird interlocks I've never seen a Smiths used on a FIAT. The Smiths one has a lot of functions...FIAT employed somewhat dumber devices.

In case you want to know what it did: http://www.triumphsonly.com/pages/technical/73-c-2.htm

As I said the wiring is original until it hits that plug, then it looks cut and taped. Why that was added is more the mystery, perhaps as a kind of anti-theft device?

[707kevin]

Weirdness...

Thanks for the info! I'll try to figure out where the wires all come from tomorrow.

[valkyrcustoms]

This may no longer be relevant but I found some literature on the Smiths control unit you were asking about. This gizmo is a seat belt/starter interlock system. It basically does not let you start the car unless you have your seat belts on. I found a diagram on how this hooks up and how to test it.
Information on this system starts on page 79 of the following link.
https://www.scribd.com/doc/28906987/Fia ... s-and-Data