So i tired to take my 96 f150 out to get e-checked (smog check out here in ohio) and before i was able to get out there the battery died. So i swapped out the battery and put in on charge and drove the truck home. Took out the old alternator and took it out to the local auto parts store for them to test it and it turned out it was bad. Ok thats fine so i went and bought a 130 amp 3G van alternator that i ready about on here ( thanks for all the forum advice) Since i already had the fire prone 3g alternator the new one went in no problem. put in a freshly charged battery and off to go get it echecked once again. Sure enough as soon as they started to try to check it the battery died and they had to push is out of the building. So ONCE AGAIN i pull a battery out of my other vehicle and drive the truck home. I pulled the new alternator out and and got it tested and it passed. but they went ahead and gave me another one which i also had them test which also passed. so i get home and install it and sure enough still aint getting a charge out of the alternator

I pulled out the wiring and checked all the connectors and they are all receiving a reading when i test them so i know theres no shorts in the wiring.

any ideas. is there more wiring i am forgetting about??

 

http://oldfuelinjection.com/public/a...ALT_wiring.gif


this is how i have it wired except that its going to what ever that thing is called on the fender

 

resting voltage is 12.4 coming out of the battery. when i start the truck is goes down to 11.7 and when i check the voltage out of the alternator it registers the same 11.7. when i disconnect the cable from the alternator and check the voltage when it is running it get nothing coming out of it.

 

I thought 96 trucks came with 3g alternators?

When you turn the igntion On, does the alternator charge
indicator light on the dash come on?

If it doesn't you need to unplug the connector at the alternator
regulator end. With the ignition On you should measure around 12 volts
on the Light Green/Red wire in the diagram you posted.

You should also measure battery voltage on the Yellow/White wire.

If you do measure around 12 volts on the LIght Green/Red wire and Yellow/
White wire, you probably have a ground problem from the alternator case/
bracket to the engine block.

To eliminate a ground problem, take a battery jumper cable
clamp one end to the alternator case and the other end
to the negative battery cable.

If no 12 volts you need to trace the wiring. In the diagram it shows
the Light Green/Red wire should be hot with the ignition On.
The Yellow/White wire should be hot all the time.

http://oldfuelinjection.com/public/a...ALT_wiring.gif

 

+1.. make sure the light comes on with ignition before you start the truck. If the bulb is burned out, it wont charge

 

yeah my came with the 3g i just went ahead and upgraded it with the larger amp alternator

no there is no dash light on the dash

the plug for the light green/ red wire doesnt connect anywhere it just kinda hangs there.

 

Are you saying you didn't plug the electrical connector into the alternator regulator or are you saying the Light Green wire is broken at the plug and not connected to anything?

The wire goes to the dash cluster. The diagram shows there
is a resistor in parallel with the bulb so if the bulb is blown
the alternator should still charge. You need to connect the wire
and verify it has around 12 volts on it when the ignition is On.

 

no the green wire that goes from the alternator out has a plug on it and thats it. there is no where the plug connects to.

the yellow and red wire connect to a fuse which goes to one wire and connects to the fender thing.

 

solenoid switch. thats what its called

 

LOL.. thought thats what u meant by fender thingy!! That LG/R wire is what energizes the regulator. You need 12volts there.

 

X7777777777777778888888888888889999999999

The Light Green/Red wire has to have +12V when the key is in On/Run position. This voltage turns the alternator "on". Without it.............no worky.

 

so where is the bloody plug at then??? i just replaced my negative battery cable for nothing?? bummer. oh well it is bigger and better then before


what color is the wire going to the green/red

 

son of a b..... stupid me had the lg/r wire hooked up to a red/yellow wire. sure enough i started the truck and the battery gauge went back to normal thank you guys so much . now the question is what does this wire go to.......

 

Typical 3G wiring below:



View of where the Light Green/Red wire attaches to the harness:



I have no clue what you are referring to with the Red/Yellow wire.

 

The lg/r wire goes to keyed 12v. Make sure the trigger wire your using is not constant 12v.