Ok... im dealing with a terrible gremlin that i just cant find...

Batteries werent charging... took them to interstate to get them charged up and tested... they gave me two loaners that were full charge and good. ok great... took alternator out and went to get it bench tested.. tested bad. ok great.. bought a new one... installed everything and what do you know.. still doesnt work.... replaced excitor from the pig tail on top of alternator because it was loose... still nothing... tested the larger connector of the pigtail and i was getting the same as battery.. . im getting consistent voltage coming from battery to starter relay to alternator (12.43)..... crank it up and it starts but not charging... i took off the larger black/red wire from the starter relay to check continuity to the alternator... it checked out good.. (thought maybe the fusible link was fried) im lost now and dont know where to look to next... im not extremely mechanically inclined so the 3G swap is out of the question... i need help and im not sure where to go to next... i dont know where all these wires run and dont want to slice open the plastic covering to follow... can someone please help. thanks

 

There is a separate wire on the starter from the alternator. Its hooked to the big post on the silanoid. (sp) The alternator has a direct wire to the + side of the battery and usually on the starter.

 

On the solenoid?? You mean the starter relay?? I'm not having problem with the truck starting I'm having a problem with it charging

 

Sounds like the voltage regulator could be bad. Look for a rectangular silver box on the passenger fender well near the starter solenoid.

 

The voltage regulator is on the back of the alternator. And the alternator checked out find when I being tested so they would have had to connect that as well

 

i have a 1994 F250 idi turbo..

 

F250 XLT where are ya buddy? ?

 

What year of truck? And check the exciter theirs usually a plug close by unplug it and jump power too it and just confirm the alternator is getting excited otherwise it wont charge. I would give you some wiring help but out of town cant look at my 94 or my 91 setup.

 

Mroth I have a 1994 7.3 idi turbo... I just bought a new exciter from ford and still nothing!! This thing can't be that complicated...So Idk where to go from here. I've exhausted all options... Cleaned all battery terminals.. Checked continuity from alt to starter relay to battery... Good.. There is two wires that go to the alternator from the starter solenoid.. One is the big black and orange which gives it power.. The other is yellow and white and that connects to the voltage regulator.. Another wire which is white and black is the exciter wire and the last wire is green and red and that runs to the cab of the truck and activates the battery light on the dash...The only thing I can think of is their bench tester is bad and the alternator is no good...

 

I am not certain of the wiring on the 94, but is there any fusible links in the wiring you are working with? Check continuity from end to end of those wires.

 

it sounds like the "new" alternator you got is no good.

 

Checked continuity and everything checks out ok. That's what I'm thinking too but I took it off and had it bench tested and they said it worked fine... Could their machine be faulty??

 

If the voltage regulator is on the back of the alternator then you all read have a 3g alternator. The green with red striped wire is the one that turns on (excites) the alternator It should have 2-3 volts on it with key on. Its is a on fuse so check your fuses See above diagram. the yellow with white stripe should have battery voltage all the time, the white with black stripe runs as shown in the diagram just check it for continuity.
good luck.

 

I ran that wire all the way back to the dash but they're so dirty and a million of them i can tell where it goes! I am guessing somewhere By the firewall harnesses but I'm not sure where. I checked every single fuse and haven't found any blown or slightly burnt ones....

 

Yep, 94 already has the 3G.