Mystery Wires

I am cleaning up the mess on my ‘72 Mach 1 (351C 2V, FMX trans, factory A/C) that the previous owners made of the engine bay wiring harness. I have three wires that I can’t identify where they originally went to. The first is a single wire coming out of a grommet in the upper center portion of the firewall. It appears to be brown with yellow dots. It does not appear to have power on it when the ignition is “on.”

The second two wires are on a connector that is next to the engine harness connector. They go through the firewall into the passenger compartment. One wire is red with yellow hash marks and the other is brown with orange hash marks. The red one has power when the ignition is in the “on” position. Is it possible these are emissions or cruise control related? If so, all of that is long gone.

I tried to upload pictures, but it didn't seem to work.

Thanks,

Gene K.

I believe the brown/yellow dot wire should have a white molded female bullet on the end; if so, it is the PRNDL lamp wire.

The other two wires are for emissions control, specifically the solenoid on the carb.

My schematics do show a R-Y(H) going to a Throttle Solenoid Positioner and a BR-O (H) wire going to an Emission Vacuum Solenoid which makes sense given they are grouped with the other wires going to the top on the engine.

The brown with yellow dots is not the one that goes to the PRND lamp which does have a white bullet connector on it. This wire is in a different location and has a black bullet connector on it. From there it goes to a female spade lug connector in a black rectangular plastic housing. It does not seem to affect anything I have found yet, so I won't worry about it for now.

Thanks

Could be for something like an oil pressure sender or temp sensor.

Could be for something like an oil pressure sender or temp sensor.

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No, those come out of the main engine compartment harness.