1969 Mustang Mach 1 & 1967 Ford Mustang

Rally-Pac WiringIn your Beyond the Basics column in the May '04 issue ("Help with PerTronix"), you advise Steve Kepley to "run a new wire from the Rally-Pac to the coil to achieve full voltage to the coil." I have a '6411/42 with a Rally-Pac and I understand your advice, but I need some clarification. Are you saying that, at the Rally-Pac, you splice in a new wire to the red/green wire (which comes from the back of the ignition switch) at the connector going to the Rally-Pac and run it to the ignition coil? Is this correct and is it easier than having to mess with the back of the ignition switch, which probably requires removal of the switch and moving the instrument panel out of the way? Can you recommend a gauge wire and any particular routing?Rich CarlsenPort Jefferson, NY

The resistor wire is wired in series between the vehicle's ignition switch and coil, so all the power flows from the switch, through the resistor, then to the coil. When a tachometer is added, it too has wires in series between the switch and resistor wire, so the power must flow through the tach, then the resistor wire and to the coil.

Mustangs without a tach have the pink resistor wire plugged into the red/green power lead you found on the back of the ignition switch. Eliminating the resistor is a simple matter of running a new wire from the red/green power lead to the positive side of the ignition coil.

Vehicles equipped with a tach have the pink resistor wire plugged into the black lead coming out of the tach. The red/green power wire is plugged into the remaining red lead on the tachometer. Eliminating the resistor requires running a new wire from the black lead on the tach to the ignition coil's positive side. As you can see, power flows from the switch, through the tach and out to the coil, then the new jumper wire. If you were to splice into the red/green wire, you would simply remove the tach from the circuit, as in the cars not equipped with a tachometer.

Routing the wire is not difficult. However, be sure it doesn't chafe through on any bracket or the firewall. A 12-gauge wire is adequate.

No GaugesI have a '69 Mach 1 with a 351W and a three-speed manual transmission. My instrument gauges (fuel, temp, oil, and alternator) quit working and the underdash wiring harness gets hot if the key is left on for a short period of time. The dash lights and turn-signal indicators work. I have replaced the gauges, circuit board, instrument voltage regulator, and wiring harness, and I cleaned the ground wire connection to the metal framework for the dashboard. Yet I still have the same problems. I don't know what else I can replace or repair. Do you have any ideas or suggestions?Bob BeckVia e-mail

Since you have replaced most of the parts that could have been bad, I have to assume you're simply not getting power to the gauge voltage regulator. The regulator is shared by all the gauges and, since they are all inoperative, I'd look for a common problem. With a 12-volt test light, carefully touch the contacts between the circuit board and voltage regulator. With the key on, the test light should illuminate continuously on one contact and blink slowly on the other contact. Be certain a good ground is maintained, as the regulator will not work without a ground. I believe you won't have power to the circuit board, and will find the plug between the underdash harness and circuit board to be troublesome. A steady light on both sides of the regulator indicates a faulty regulator

Do all your testing of the gauges with the key in the accessory position so the ignition circuit is not on