charging problems...help?!?!

[ninety15.0]

Hey guys...i have been having this rediculous charging problem for the past week now. I changed my speedo cable and speed sensor last weekend and i had my dash + instrument cluster all apart. Well after i put it all together, my car wouldnt charge...at all...my volt gauge was down at 9ish volts. Of course i suspected the alternator first so i took the voltmeter to it and it was only pulling like 10 volts at idle?! So i changed it out with another 3g 130 amp i had sittin around. No go...it did the same thing. My battery is drained so low right now that it wont even run the ignition after i jump the car and it sits for a few minutes idling. So what could i have done to it for this to be happening. What are the odds that i killed one alternator and the other one i got is defective too? I know an alternator should be pulling like 14-15 volts at idle...so something is pulling crazy current right now that the alternator cant keep up with? HELP

 

[ninety15.0]

By the way i am running a 3g 130 amp with 4 gauge wire and a 120amp circuit breaker inline. The breaker hasnt tripped and i have tested all the segments of the chargeback wire from the alt. to the starter solenoid/dist. block to the battery...and the voltage is all consistent with the voltage that the alternator is putting out.

 

[jrichker]

When you took the dash apart, you damaged the circuit
that tells the alt the ignition switch is on and to turn on
the voltage regulator. That circuit consists of the alt
warning light and a 500 ohm resistor. Look for the
lt green/red wire, circuit 904 in the following drawing:

Diagram courtesy of Tmoss & Stang&2birds

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

 

[ninety15.0]

Wow...thanks for the help...that would have never crossed my mind. Where exactly is that resistor located? is it on the back of the instrument cluster? thanks in advance.

 

[jrichker]

The resistor jumps the Alt Warning light. The purpose of the resistor is to provide current for the circuit if the Alt Warning light burns out. The resistor and the wires that feed it are the ones to look at for damage.

 

[ninety15.0]

I think i found the resistor on the back of the instrument cluster. I tested it with my DMM and it read a perfect 510 ohms like it says. The resistor seems fine...and i took a quick look at the harness and found no visible problems. I think the problem may have just been the connector not plugged in properly. All that bullsh/t and it may have been a loose connector. thanks for all the help jrichker! the wiring Guru!