I get nothing on I and 12.17 at A and at alternator output

 

Got it. Your fusible link is fine. The problem is that you're not getting any power at the "I" terminal of the regulator plug with the key in RUN (that's how you did it, correct?)

With the ALT light setup, power applied at the I terminal of the regulator is what initially provides power to the field circuit of the alternator, which is necessary to get it started. Once the alternator starts spinning with the field circuit energized, it produces voltage of its own, which sends a signal to the regulator to shut the ALT light off in the dash, and also turns the regulator "on." If the regulator never gets that signal at the "I" terminal, the whole process will never get started, and the battery won't charge.

You have a wiring problem - you can change out regulators and alternators all day, but it won't solve the issue. Hot-in-RUN power from the ignition switch powers one side of the ALT light - the other side of the ALT light runs out to the I terminal of the regulator. That is to say, the regulator is actually powered through the ALT light. You have a break somewhere in this circuit, or it's not wired correctly. There is also a 15-ohm resistor in parallel with the ALT light, to keep the system functional in case the ALT light burns out, which would otherwise break the circuit.

Also:

This wiring is wrong. GREEN with a RED stripe is typically the power downstream of the ALT light that runs to the I terminal of the regulator. The S terminal should go to the stator of the alternator (that's what the S stands for). If you have an automatic choke, the choke also connects to the stator terminal of the alternator.

 

So do I need to replace the harness. I did the test correct to answer your above question? Any suggestions other than new harness?

 

You can replace the harness, or investigate and fix the one you've got. At the end of the day, you've got what looks like the wrong signals going to the wrong places, and the right signals not showing up where they should.

 

Took dash out. Check green-red (I) and continuity was good through alternator light. Alternator light burned out. Replaced. LIghts up with key on and goes out when truck starts however readings are the same. Where is the resistor that is parallel with the alternator light?

 

That's a good step forward. Do you still have your regulator connected as you described in post #8? If so, that needs to be corrected.

If the ALT light goes ON when you first turn the key, and goes OFF once the engine starts, then this tells you that the regulator is closing the field relay - the only way it can do this is if the alternator begins to charge, unless you have more wiring issues that are tricking the regulator.

If the wiring is fine, and your ALT light is going out, then the alternator is charging now - just not enough. Measure the voltage across the battery terminals while the engine is running. Then connect a jumper wire from one of the regulator mounting bolts to clean, unpainted metal on the block (ground) and see if the reading increases. If it does, then there are some grounding issues to take care of.

I'm not sure how the 15-ohm resistor is implemented on this generation trucks. On later model trucks, it's a discrete resistor on the back of the cluster. On several models of sedans, it's a long resistor wire that snakes through the wiring harness. This generation of trucks would be one or the other.

 

Yea I fixed the wiring from post #8. there is a resistor on the back of the cluster. Do I just do a continuity test to see if it is good

 

It is fixed. Short in bulb in the dash. It is putting out 13.5 idling. I am still going to take to advance auto for test. Thanks everyone for all your help.

 

Glad to hear it's fixed - I don't understand how though. If the bulb was shorted, it wouldn't have turned ON then OFF when the engine started (it would always stay OFF). Also, the regulator will still function with the ALT light shorted across itself because the regulator would still receive keyed power. I might not be understanding your statement correctly.

 

good job on both the help fmc400 and the work wsnead56 for gettin it done. im working on a bronco some one has slung a slew of parts and cut some wires on it.