Not charging, need wiring verication

[Cribbs74]

I haven’t mentioned it because I assumed it was only one side of the idiot light and is a non player. Also it wasn’t mentioned as being that important Apart from naking the alt light illuminate. It does exist and is connected correctly. The diode that’s inline could be toast and I need to confirm this evening If that is the case. 71Fast brought up the diode.

Thanks everyone, more to come! I feel I have a way forward now.

 

[midlife]

This is an excellent document describing how alternators and voltage regulators work. Hope it helps.

 

[71fast]

I learned a lot about charging from How Alternators Work file that Midlife posted. Excellent write up.
I was thinking about Cribbs74 alt. warning light not working and thought it might have something to do with a diode.
The diode is inline with wire 640 on my old 71 non gauge harness to prevent dieseling. Harness was for a 302 with solenoid.
Only used on 250 and 302 engines with anti diesel solenoids.
So Cribbs74 probably doesn't have one.
I still wonder how that diode could prevent dieseling.
The diode is not on any of the wiring diagrams. Located next to the voltage regulator.
I see the diode are available to buy on Ebay.
Anyway, step 1 says the green wire 640 should have power with key on or the regulator won't start.

 

[midlife]

Never seen a diode in any of the wiring I've worked on in the 18 years I've been in business!

 

[Cribbs74]

So….. Ta Da! It’s fixed. Turned out to be a cut green/red wire in the headlight harness directly under the radiator along the crossmember. I would like to thank each and every one of you for chiming in and offering advice. Your help was definitely needed.

I am attaching a picture of my multimeter for proof!

Ron

 

[Hemikiller]

Never seen a diode in any of the wiring I've worked on in the 18 years I've been in business!

There's one on my '71. To be honest, it's the only one I've ever seen.

 

[Cleveland Crush]

So….. Ta Da! It’s fixed. Turned out to be a cut green/red wire in the headlight harness directly under the radiator along the crossmember. I would like to thank each and every one of you for chiming in and offering advice. Your help was definitely needed.

I am attaching a picture of my multimeter for proof!

Ron

Good job finding that hidden gremlin!

 

[midlife]

There's one on my '71. To be honest, it's the only one I've ever seen.

Is that your Mustang? With factory ignition system? That doesn't look quite stock to me...

 

[Hemikiller]

Is that your Mustang? With factory ignition system? That doesn't look quite stock to me...

That's mine and it's not stock, but the diode was in place when I bought the car in 2001. It has an NPD repop alternator harness, but the engine compartment harness is OE Ford.

 

[dON]

Good job finding that hidden gremlin!

Great job always a process enjoy