My 1991 f250 7.3 idi and the issue is that my truck won’t charge unless I jump power to the field wire. After that it charges fine. I do have a broken ground cable and I have replaced my entire charging system.
Charging issues
- Thread starter BlueHound
- Start date
Have you replaced/checked the voltage regulator on the passenger fender, behind the battery. These alternators use and external regulator, and if it's not telling the alternator to charge, it won't.......
Unless you've done a 3G conversion........ it's internally regulated.
Unless you've done a 3G conversion........ it's internally regulated.
Yes I have replaced it. As a matter of fact that is where I jump power to the field wire. I also forgot to mention that the battery light never comes on not even when I initially turn the key on, yah know when all the lights should come on.
Macrobb
Full Access Member
And make sure the external regulator is well grounded. That'll definitely cause an issue.
if that light doesn't work, the battery won't charge.......
Macrobb
Full Access Member
Good point. The external regulator actually gets it's initial power supplied via that light, which also limits the current(so don't think you can just eliminate the light and run it straight to power).
If you do 'custom' wiring, you can just find an old taillight bulb or marker, hook that between switched power and the terminal on the voltage regulator. Light should be on with engine off, then go out as soon as the alternator starts making power.
If you do 'custom' wiring, you can just find an old taillight bulb or marker, hook that between switched power and the terminal on the voltage regulator. Light should be on with engine off, then go out as soon as the alternator starts making power.
sailorman524
Registered User
I went through 3 regulators from Napa just get one good one. Finally switched to 3G and never looked back.
79jasper
Chickenhawk
It's a style of alternator. It uses a internal voltage regulator.
Try "3g swap."
Sent from my SM-G892A using Tapatalk
Try "3g swap."
Sent from my SM-G892A using Tapatalk
This! I fought with regulators till I got a good one. The more expensive ones seemed to be junk. Im running the cheap one from orileys and I carry a spare.
whiteboyslo
FNG
3G Tech Article: https://www.oilburners.net/threads/130-amp-3g-alternator-install.14573/
Better 3G Tech Article: https://www.ford-trucks.com/forums/1156489-how-to-3g-install-for-83-92-idis.html
Mike
Better 3G Tech Article: https://www.ford-trucks.com/forums/1156489-how-to-3g-install-for-83-92-idis.html
Mike
3G wiring.
You must be registered for see images attach
I’m not sure that’s true on a brick nose. It is on an OBS I’m think. I went through this with someone a while back. I think it was Brian working on asmith’s truck.
@IDIoit
Macrobb
Full Access Member
Don't do this, though.
The yellow/white wire should *NOT* be attached to the alternator output terminal. Run that wire all the way over to the fender well solenoid(battery terminal side), or whatever connection point you have that is as close as possible to the battery.
This is the 'voltage sense' wire - If it's attached to the alternator output, any voltage drop due to current being drawn by accessories will result in lower voltage at the battery.
If you put it at the battery, the alternator senses any drops and increases the output voltage to compensate... makes for a very nice, consistent output voltage, no matter the load.
This is also what the factory 3G trucks did, like my '93.
Similar threads
