as I understand it, it seems to be a perfectly operational system.

the relay will get a signal from the ignition switch when you start the car(search violet wire mod) which will then shut off the plugs. if you do not start the car, the plugs stay on, but the "wait to start "light will go off sooner or later, depending on temps.

your right on the the 2 sensors- one is for the gauge on the dash, the other for the GP system.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.