Ignition Wiring

[poison heart]

I finally got my old '74 Power Wagon running. The previous owner rigged a plastic switch for the electric fuel pump and the ignition on the same switch. Well, I broke the switch and when I tried to reinstall a new switch I'm not getting any spark at the coil. I used a volt meter and I'm not getting any power at the coil.

My question is, How can I bypass all the old ignition wiring and just go from the coil to the ignition switch? There are 2 wires on the coil. Which wire goes where?

[buck99]

The simplest way is to go to the fuse panel, put a jumper between a switched fuse and an unswitched fuse. That powers up all the circuits normally activated by the ignition switch.
This would only be for testing as the unswitched fuse would be carrying the full load of the switched circuits, so pick the biggest fuse like maybe the cigarette lighter fuse.

[poison heart]

I know the fuse panel is in the daash. how hard is it gunna be to run a wire to it? What do you mean mean put a jumper between a switched fuse and an unswitched fuse? The only electrical things that work on my truck are the lights, brake lights, fuel pump and ignition.

There are 2 wires that go to the coil. Where do those go and how do they connect to the ignition switch?

[Rayven]

if ur interested i have a dash harness for a 77 should be the same for a 74

[bherder]

Does your rig have the factory ignition system? As in factory/Mopar ECU, coil, ballast resistor, etc?
If so, you can't run a wire straight from full voltage (12-14v) right to the stock coil. The coil was designed to run off of 9-10 volts. (That's what the ballast resistor is there for, to drop the voltage)...
The only time, it runs off of full voltage, is when you're cranking the engine to start it. As soon as you let off the key, the ballast comes back into the circut and drops the voltage for the ignition system.
If you run the stock coil on full votage, it'll end up cooking it. (How long, I don't know)

If you don't have the stock ignition anymore, nevermind ;)

Here, maybe this will clear things up for you....

[poison heart]

Thanks for that diagram. The previous owner took out the original switch. He rigged the ignition and the fuel pump on one switch and then rigged a button for the starter. I want to skip the harness that's already there (since theres a short or something somewhere in there) and just run a whole new wire from my new switch straight to the coil.

I have a hot wire at the switch already. It's black. The one that went to the ignition was blue. If I replace the blue wire, where do I run it?

[bherder]

Look at the schematic I posted. Trace what the PO did... How he had/has it wired. Look at the way it's supposed to be on the schematic... Again.....
If you have a STOCK ignition coil/ECU .... you CAN'T just run 12-14v to all points in the ignition, all the time. You'll cook things.

[poison heart]

Ok, My ignition switch is long gone. It is just a toggle switch. So I don't have 2 the 2 wires that are shown running to the ballast resistor. I only have one wire and its blue and runs through the harness. There must be a short somewhere because I don't get any power at the coil. I'm pretty sure the ignition is stock. Since I only have one wire and there must be a short somewhere, how can i bypass the harness? Can I just run power to the ballast resistor? That will make it run on 9 volts all the time even during start up right?

[poison heart]

Ok, I went out to my ranch today and there is no ballast resistor on my truck. How is the coil grounded? There are 2 wires. Is one a ground and one hot?

[Delray Dude]

I'll take a stab at this one.

If you have an aftermarket coil (non-mopar) you can run it on full 12 volts.

If the system is electronic ignition, you should have a box on the firewall with a plug that looks like the one above in the diagram. remove the plug - usually a phillips screwdriver in the center holds it on.

look and see if the box has 4 or 5 prongs.

The coil on standared Mopar ignitions have a (switched) constant positive lead to the one terminal on the coil - but stock Mopar coils have to live with the voltage drop via the ballast resistor.

The other is grounded via the ignition box - which produces the spark in the coil. The 2 wires on the electric distrib go tot he box and give the signal for the box to ground the coil negative producing the spark. So, you need to run a postive wire to a switch on the dash - then to the coil postive (coil will have it marked on it). You also need to run this positive lead to the termianl #1 on the box. The coil negative lead should go to the corresponding terminal on the box.

If you have a points distrib - this will be different.

[Speed Dragon]

On a points dizzy, the has a switched positive like usual, but the negative runs to the points in the dizzy instead.