Alternator headaches please help!!!

[mbuchman]

72 F100 4X4 lwb 360/c6. My alternator seems to be not charging (as in the battery died and with fresh battery in if you remove the positive engine goes dead immediately. pardon my ignorance but how do i test if it is charging other than that? basically im desperate for some help on this because i have to drive myself and my fiancee to ohio from upstate new york in a week. my gauge cluster has been replaced fyi to aftermarket and a billet panel so from checking the diagrams on here there is a wire going from the voltage regualtor to the cluster. would that not being hooked up affect this at all?

[customcrewcab]

no that wire would not. it only gives power to the gauge. if it was hooked up it would tell you how many if any volts your getting. you might have to pull the alt and take it to an auto parts store and have it check. it has to be that or the regulator

[mbuchman]

is there a post off the alt or regualtor i could meter to see if its just a connection?

[customcrewcab]

well it would be off the regulator because it regulates the power coming out of the alt. i would change that out because it easy and i think around 15 bucks. if it still dies when you pull the postive cable off the the alt.

[customcrewcab]

hey most any wire that has keyed switch power going to it you should be able to run you volts gauge off of. just as long its not a coil wire.

[Thunderfoot]

my gauge cluster has been replaced fyi to aftermarket and a billet panel so from checking the diagrams on here there is a wire going from the voltage regualtor to the cluster. would that not being hooked up affect this at all?

If your stock gauge cluster didn't have an Amp gauge and only had an idiot light, your alternator will not charge as it is missing the Exciter wire being hooked up...

[mbuchman]

thanks but i had the anp gauge not idiot lights. besides NAPA is delivering me an alternator and voltage regulator today. I love working where they deliver twice a week at a discounted price

[mbuchman]

[mbuchman]

just by chance if the exciter wire isnt hooked up anymore although i did have gauges what should i hook it to? i ask because new alt and voltage reg and still no charge. and as i sit i think it has to do something with changing the cluster

[seattle67]

Here is a basic hook up diagram that hopefully will help.

[Thunderfoot]

For your 72 look at the attached diagram that I marked up to show the exciter wire rout. It is a Purple wire that comes from the ignition switch and ties into the wire (Green-red striped) that went to the Amp gauge.

This wire is what tells the Alternator to charge, it is also a resistive wire where it is purple. Make sure that when you disconnected the stock gauges that this Green wire that went to them is not shorted out somewhere, or that you tied into it with something else that is drawing power...
You can also go to the Voltage Regulator and check that Green-red striped wire has voltage on it with the key in Run.

[Wes]

Do you have battery voltage at Batt term on alt ?

[mbuchman]

so yeah it was the exciter wire... i feel smart. although i dont know if it was a p.o. or not but i had no green/red in my harness at the cluster mine ended up being a red only. but now it is fixed. and i feel a little silly but i guess new alt. and voltage regulator is a good thing dont have to worry about those any time soon. thanks for all the help everyone. also it just goes to show you dont assume you have to spend cash first. sometimes it is just a wire.

[willowbilly3]

If you installed the NAPA reg you might want to keep your old one in the truck. I snag all the original Ford ones I can find because a used one of them is better than any aftermarket new one.
Also you can full field the alternator by unplugging the regulator and putting a jumper across the first and third connectors in the plug. Do not rev the engine as it can create excess voltage in this mode. Those alternators seldom fail, usually it is the reg.
I know this sounds like a broken record because it is about the 100th time I have said it but STOP pulling off the battery cable when the engine is running. That was fine when cars had a generator 50 years ago but you are going to seriously fry some stuff doing that. At least you can loose light bulbs and if you do it on a computorized car you might just total it out (as in repairs would be more than the car is worth)