Alternator Not Charging Battery?

[1987cp]

Sounds like time to make your own harness with at least 8 AWG for the charge cable.

[86VickyLX]

Sounds like time to make your own harness with at least 8 AWG for the charge cable.

Why go through all the trouble of making a harness for an obsolete alternator. If you're gonna run a new harness, go to a 3G alternator. And buy the pigtail from your auto parts store, and run a brandy new charge cable to the starter solenoid.

[1987cp]

Actually, a 2G harness is readily converted to 3G, and vice versa. I'm still running a 2G in the formerly-3G-equipped P72 with the 2G stuff just piggybacked right on (so it can be put back to 3G configuration without cutting).

[gadget73]

The ground at the voltage regulator comes through the mounting screws. There is no ground wire in that flat plug. If you have rust under the mounting screws, it won't work properly. Try pulling the regulator and cleaning that area up with a wire brush.

The wiring does look sort of bitched up. You can re-wire it fairly easily. F on the regulator goes to FLD on the alternator. S on the regulator goes to S or Sta (i forget how its marked) on the alternator. Thats really about it, the circuit is pretty simple.

[july7543]

Update

Well, after taking Gadget's advice. I cleaned up the ground connection to the regulator and I am now seeing 14.5volts of output from the alternator at idle.

I do now, however, need to work on the fact that the Amp light does not lightup at startup. I will light up if I ground the green/red wire that is in the coupler. However, currently that wire is set up to do nothing. The wiring diagram in the manual shows that there are two wires connected to the amp light negative side. A R/LG and a LG/R wire. One of them is not used. I can only guess that the one that should be used is not being ground. (Or my wiring is no good and that is the one that should be grounded)

I should note that with regard to the coupler, there are plates at the back that force the wires into the locations that they are in. It is reasonable that the light green/red wire is the one that is not used and that the black wire is intended to run up into the car.

[gadget73]

What terminal is the green/red going to? It should be on the I terminal.

[july7543]

Out from the I terminal is the black and orange wire. It goes to the aforementioned coupler that connects it to a black wire.(That leads into the along with the R/LG wire) Is it possible that this black and R/LG wire are switched and the R/LG wire should be connected? I think that this may fix the problem.

[gadget73]

Disclaimer: I don't have an 89 manual to reference, this comes from my 86 book which ought to be the same.

according to what I have here, the orange/light blue should go from F on the regulator to Fld on the alternator
white/black goes from S on the reg to Sta or Stator on the alternator
light green/red goes to I on the alternator, and from there goes to the idiot light (no black wire at all)
yellow/white goes from A on the regulator through a fuse link to the battery. Its also got the little condensor dealie on that wire.

I'm thinking there is either something unusual with your wiring, or maybe its to do with the Instaclear windshield wiring. I know that interfaces with the alternator somehow, but I don't actually know the details on that.

[85crownHPP]

If it was a dealer added option, maybe the technician was hung over that morning... lol

[july7543]

Update

It seems that when I ground out the light green/red wire. The amp light kicks on at startup but will stay on. I need to get my multimeter back and verify if that is for good reason or not. In any case. I've attached a summary of the what kind of wiring I have going on.

[july7543]

BTW

Can anyone tell me what color of wire they have coming from their external voltage regulator from the I (Closest to Engine) terminal. The Hayne's wiring diagram suggests that the voltage regulator determines when to ground this wire out and that the voltage relative to ground is always supplied to the Amp light. Does this sound correct?

[july7543]

Strike Out

Strike that previous thought on the purpose of the Green/Red Wire. From what I can gather. The Amp light works this way. To one side of the light, battery voltage is supplied. To the other side of the light, alternator voltage is supplied. Thus, no current flows. When ignition is turned on, there is no alternator voltage present so current flows through the light due to the voltage difference relative to ground. When the alternator fires up, there is no relative voltage so no current flows keeping the light unlit. In my case, the LG/R wire is not connected to the voltage regulator so the light will no illuminate under any circumstances.

My thought is that it needs to be wired into the voltage regulator. I am not sure what the black wire is for but it doesn't appear to be a ground. I will go ahead and check to see if there is voltage at the I terminal if there there is, I will wire the LG/R wire into there. If there is no voltage, I can only assume that both of my voltage regulators (I've swapped in the OEM one for testing) are bad.

Can anyone check if their I terminal has voltage at that location?

[85crownHPP]

I think you're right... Ive been monkeying with the wiring on my 85 (which was externally regulated) during the 3G swap, everything fron the alternator to the regulator is sitting in my basement.
While probing around I did read power on that green/red wire, and it does go to the 'I' terminal on the regulator. I also noticed that this voltage had a load on it already, because it didnt short my meter when i grounded it Evidently you also need this to charge, so it looks like you solved your problem!

[july7543]

No Luck Yet

Well, it looks like I haven't solve things entirely yet. It appears that I always have voltage at the regulator I terminal (Ignition on or runnning) and as a result the light won't light. Even when I took the alternator voltage away it didn't light. I'm going to study the wiring further. Any thoughts?

[86VickyLX]

Those idiot lights are weird. I have seen myself the weirdness of the light. Get this, a new battery for an '88 Grand Marquis, right, light comes on in run position, with engine off, with engine on, the light stays off, but the alternator did not charge. This alternator zapped the battery of basically all of it's power to the point no lights came on in the car. The light was never on as the car was running, even though there was no charge from the alternator.