For 1990-2009 cars

The CIGAR/DLC fuse applies voltage at all times to the cigar lighter through circuit 440. The cigar lighter heats up, when pushed in, completing the circuit to ground through circuit 1450. When the heating element sufficiently heats, the cigar lighter opens the circuit.

The FRT PWR SCKT fuse applies voltage at all times to the front electric accessory plug housing through circuit 1940. When plugged in, the accessory completes the ground circuit 150, and applies ground to the front electric accessory plug housing.

The RR PWR SCKT fuse applies voltage at all times to the rear electric accessory plug housing through circuit 2540. When plugged in, the accessory completes the ground circuit 850, and applies ground to the rear electric accessory plug housing.