Ford voltage reg

butch27 · July 02, 2007, 11:18:01 PM

I'm wiring my car as a '68 Ford BUT without the idiot light. So where does the "I" from the reg.go to ?

enjenjo · July 02, 2007, 11:21:22 PM

To the accessory side of the ignition switch. You may need a diode to control current flow.

butch27 · July 03, 2007, 12:02:58 AM

Frank: One diagram shows to wire "I"to alt. excitor ( brown wire)??

enjenjo · July 03, 2007, 09:10:44 AM

Quote from: "butch27"Frank: One diagram shows to wire "I"to alt. excitor ( brown wire)??

Yes, thats would be the same thing. When you first start it up, you need a bit of current to " boot" the alternator to charge. So the factory used an alternator exciter wire with the idiot light in it to limit current.

If the alternator is not charging, the current finds a ground at the alternator, and the lamp lights. As soon as it starts charging, the lamp goes out.

When you shut off the engine, the current will backfeed from the alternator to the ignition switch. The idiot light acts as a current limiting device, and will not supply enough power to keep the engine running. With no idiot light in the circuit, there may be enough power from the exciter wire, the engine may not want to shut off. A diode in the exciter wire will only allow the current to flow from the ignition switch to the regulator, and will keep the engine from running with the switch off.

An electric fan can cause the same problem. A diode is the cure there too.

butch27 · July 03, 2007, 10:43:00 PM

O.K. I found a wire marked Alt. Excitor . What diode do I use and where should I install it in the wire . I hate splices.

enjenjo · July 03, 2007, 11:07:34 PM

Well, you can order one from Ford, but I usually get one from radio shack I think it's a 5 watt. under $2.

You can install it at the ignition switch, under the dash, or at the regulator.

zzebby · July 04, 2007, 02:53:36 AM

The diode is like a one way valve and only lets current flow in one direction. The little arrow on the side shows which way so be sure you have it right.]

t-vicky · July 04, 2007, 11:06:54 PM

Sounds like what I need to put on my cruise control. If the cruise is turned on even with the key turned off & you step on the brakes the digital gauges come on. Both are on the acc side of the switch. I should put it on the brake wire from the cruise right?

enjenjo · July 05, 2007, 09:41:47 AM

Quote from: "t-vicky"Sounds like what I need to put on my cruise control. If the cruise is turned on even with the key turned off & you step on the brakes the digital gauges come on. Both are on the acc side of the switch. I should put it on the brake wire from the cruise right?

Put it on the brake wire to the fuse.