[L Johnson]

Does anyone have a wiring diagram for a '74 Challenger? or know where I can purchase one?
We installed a 360hp crate engine, upgraded the tranny and differential. We had finished putting on headers and new exhaust, on the way to the gas station to have the car inspected, the amp gage pegged full charge twice and went back to the middle. We arrived at the gas station and turned the key off, it still runs.

I replaced the voltage regulator, disconnected the tach trigger wire from the coil, disconnect the big wire from the alternator thinking there might be a feed, we disconnected the wiring plugs next to the steering column hoping we would find a short, NOTHING, we disconnected the ignition switch and we still have voltage to the ballast resister and coil..

ANY IDEAS WOULD BE GREATLY APPRECIATED

[Joel]

Uhh, that is a good question, Dave any comment?

[dave-r]

You don't need a 1974 wiring diagram. You need any mopar wiring diagram of that sort of age so look at the ones I do have posted here. One other thing you need is someone to give you a hand who has a basic understanding of how an ignition system works.

One of the terminals on your ignition switch is connected to the battery. When you turn it to the first position it connects the battery to one end of the ballast resistor. The other end of the ballast resistor goes to the coil. When you turn the key switch a bit more to start the engine it connects the battery to the same side of the ballast resistor as the coil. This gives you full voltage for starting. Letting go of the switch allows it to flick back to the 'run' position which gives the coil a reduced voltage via the resistor.

When the switch is off you should have no voltage at the ballast resistor at all.

Someone has either connected up the switch badly or 'hot wired' the coil directly to the battery. Should be very easy for anyone that knows a little about electricity to sort out.

Good luck.

[dave-r]

See also Technical Area:Electrical:Electronic Ignitions on this message board.