Gen light on after Alt swap

[ThinLizzy13]

Just did an alternator swap on my 63 F100. I used the standard Ford alternator with external regulator. i hooked everything up, and it is charging as it is supposed to. Despite it functioning correctly the gen light stays on and gets brighter and I rev the engine
Am I supposed to change something in the wiring to the generator dummy light?

[Leeroy]

I'm not 100% that the stock wiring for the generator vs an alternator is the same, but on the alternator version the light is used to excite the fields and start the charging process. You say it's charging as it's supposed to, have you checked what the system voltage is one it's charging? To me, the light being on means it's not charging OR there is a problem with the regulator itself (I've had both happen.)

[ThinLizzy13]

I was thinking the same thing when I saw the light on. But I'm getting 13.5ish at idle and 14.5 holding the RPMS up at the battery...

[Leeroy]

13.5 Sounds reasonable if it's a original style. Regulators are fairly cheap your side of the pond unless you want all the original decals on it. Worth maybe trying a different regulator? You'd have a spare if it turns out it wasn't tr regulator

[ThinLizzy13]

Thanks for the help Leeroy. I have about 5 or 6 extra VR's laying around that all tested too high voltage The one I was originally testing with was off my 67 that I know is working. I thought maybe some of the others might make the light go off.
Turns out my Stator wire wasn't completely tight on the alternator. Snugged it down and the gen light went off and the extra VR's stopped putting out high voltage. It always seems to be the simplest solution.
I saw some posts on other forums about putting a 15ohm resistor in when converting to alternator which made me think I was missing something. Guess I don't need to do that

[Leeroy]

Glad you got it sorted. The simplest things are usually the easiest overlooked (Dont ask how I know!) Not sure about the resistor wire sorry, I have no experience from gen to alt, just alt to 3g!

[Toyz]

The 15 ohm resistor in parallel with the lamp is to allow the alternator to continue to function should the bulb burn out.
Paul

[Leeroy]

^^^^^ Not a bad idea I guess. Although the light socket isn't too hard to grab from behind the dash and replace on the slick. A RHD mustang on the other hand.........