kalli

Hi all,

very long time no hear. I still have my mustang, but I got father in the meantime and had so many other things on my plate that I just didn't get around the forums anymore. hope all are well.

I'm having a problem with my system not charging at all. originally generator, was converted to alternator. so my wiring should be exactly as it is in a 65 mustang (just different colors).

anyway ... what I checked so far:
- the alternator light (idiot light in dash) does not come on,. it is off when ignition is on and it is off when driving (engine running). battery has 12.5 volts ignition on or engine running. it lowers of course with time and i simply recharge the battery over night.
- I assumed the idiot light being broken. since the light is connected to ignition switch and the other side to voltage regulator i unplugged it from external voltage regulator (I-terminal) and connected that cable directly to ground with ignition on. The lamp comes on, which for me proves all wiring from dash to regulator is ok.
- i unplugged the cables from voltage regulator and i bridged 'A' and 'F' (jumped it with a wire). This causes the system to charge at full throuttle. battery voltage goes up to 13V, 13.5V, 14V ... within about 30 secs. at 15V I disconnected. With this I believe the alternator to be ok as well.
- i connected the alternator, regulator to battery minus just to be sure they have proper ground
- i changed the voltage regulator with one from a friend that we 'believe' is good. we have no proof. he said he pulled it ouf of his car, should be fine. but we have no way to verify.

Anyone any ideas? Is there a rock solid way to test the external voltage regulator with multimeter? ohm? voltages on pins?

all the best

Kali

Starfury

Hey Kalli, welcome back

That test you performed confirmed that the voltage regulator (or wiring) is bad. The alternator is putting out voltage, it's just not getting past the regulator.

kalli

thanks Tad :-) I'l redo all cables (A-F-S) to alternator and if that doesn't fix it I'll simply try with a new regulator ...

just a quick one about the wiring. I wired
I- idiot light from dash
A- Directly to alternator output (marked as BAT+). to be more detailed i have a wire from 'A' and from BAT+ meeting at battery side of starter selonoid
F- to alternator field (no other connections on either side)
S- to alternator stator (no other connections on either side)

am I missing something or is this ok?

Kalli

Gun Jam

Hey man welcome back....check it out Im a Mod now!!! The pinnacle of my mustang adventures.

It does sound like a regulator issue...or wiring issue. It does appear to be correctly wired. "I" I think is actually ignition but you are correct.

Here is a wiring diagram that may help





-Gun

kalli

congratulations and thanks man :-)
looking at that diagram, with engine off ignition on, the 'I' should go straight to ground (well with (0.3+10+50) Ohms. if that were the case in my regulator the idiot light would come on. I'll check once more my stator wire, to make sure all is ok there (not causing 'A' to feed back) but I'm quite convinced it's the regulator alright.

Thanks Tad and Gun. Anyone else from the old boys left over? :-)

Gun Jam

You aint reading that too good buddy.

"I" Does not run to ground it runs to + on battery even if you skip everything else

kalli

thx! i meant the voltage regulator side. the cable from my lamp goes to 'i' and inside the regulator straight to ground (with ~60ohms inbetween). This is what should cause the idiot light to come on (ignition plus on battery side of lamp from ign switch and ground through reg). once engine is running both sides are about 14V, no light

Gun Jam

that sounds about right!

bop11

Sounds like the one side of you light and the 15 ohm resistor are not connected to the center terminal on the ignition switch. If power doesn't pass through the light / resistor combo, the field relay never gets energized. The field relay keeps the alternator from acting like a motor when the ignition is off and the engine is not turning. With out energizing this relay, the alternator has no output. The 15 ohms resistor is so it works even with a burned out bulb.

kalli

hey bop11, thx for info with the field relay, just looking at diagram trying to understand that. If you check on my original post: the idiot never comes on when ignition is on (no matter if engine turns or not), only when I connect the wire that goes to reg 'I' terminal directly to ground. then it lights. with this i don't understand your post about light not connected to ign switch?