Help me ID this please.

[Tuckerjr]

I finally was able to track down an issue I was having where the car would stop as soon as I turned the key from start to run
The MSD control box wasn't getting power when switched to run. I traced it back to it's source and found this.

It was connected where the bare wire is in the pic with one of those connectors that lets you tap into another wire. We were not getting anything through the connector with a test light I removed the connector, wrapped the wire going to the MSD around it and it fired right up.

Can anyone tell me what the red part is in the pic? The green jumper wire was there from the previous owner as well, not sure what this is and if I can bypass/remove it.
.

 

[Dana67Dart]

Red part looks like a connector. The part it is attached to looks like a relay, what car, year, where is the device located

 

[Demonic]

Ha. Is it a ‘75 seat belt relay? Get a heat shrink butt splice and eliminate it.

 

[AJ/FormS]

Our cars have two ignition circuits going from the ignition system; One from the start position and another from the crank position. For aftermarket ignition systems, these two have to somehow be joined together.
The cheap-O way is to run the blue wire and the brown wire together. But this leaves the start relay energized and sometimes the starter won't shut off.
The better way is to run the poweramp off the run circuit and relay the brown wire to send 12 volts to it whenever she's in crank mode.
This should be detailed in the MSD instruction manual.
Since the MSD only uses these signals to turn on the amp, there is very little current draw thru the relay, so it only has to be reliable. The amp has it's own battery power-supply.

OOPs I think I answered a non-existent question,lol.

 

[67Dart273]

Our cars have two ignition circuits going from the ignition system; One from the start position and another from the crank position. For aftermarket ignition systems, these two have to somehow be joined together.
The cheap-O way is to run the blue wire and the brown wire together. But this leaves the start relay energized and sometimes the starter won't shut off.
The better way is to run the poweramp off the run circuit and relay the brown wire to send 12 volts to it whenever she's in crank mode.
This should be detailed in the MSD instruction manual.
Since the MSD only uses these signals to turn on the amp, there is very little current draw thru the relay, so it only has to be reliable. The amp has it's own battery power-supply.

OOPs I think I answered a non-existent question,lol.

Uh the above should not be true. The brown bypass circuit is a separate key contact from the yellow start circuit

So far as the op, whatever that wiring is, should not be connected to the MSD run circuit

As said it is VERY likely the seat belt interlock. Does it have a reset button on the other side? The looped bypass is there to bypass the device and that should be your "start" circuit to the starter relay. has nothing to do with "run."

the normal way to hook an MSD is to connect the "small red" which is essentially a "trigger" wire to the original "run" circuit, with the brown bypass jumpered to it. IN FACT you can even leave the original ballast resistor in there, and simply connect the "small red" to the original coil+ wire as long as the bypass wiring is intact

HOW THIS WORKS

You have two circuits feeding the coil/ ballast, originally. IGN1 "run" is ONLY HOT with the key in "run." During start, it goes dead

During start, there are TWO ignition switch contacts "hot." One is the yellow "start" wire going to the start relay, t he other is the brown which bypasses the coil resistor. It originally connected to the coil+ side of the ballast resistor

 

[H22A4]

It would be helpful if you stated what year car you’ve got and drivetrain (auto or standard).

Just guessing but I think it’s the 1974 seatbelt interlock relay that only exists for one year.

 

[Tuckerjr]

Yes, it's a 74 Dart Sport with an automatic transmission. Thanks for the help everyone

 

[72bluNblu]

That is most definitely a ‘74 seatbelt interlock.

I just had to eliminate that little guy on my car as well. Ran fine for years with it hooked up with no sensors, but the interlock died and killed my car too. Bypassed it with help from @67Dart273 , problem solved!