weird charging issues

[Mizark347]

I am having some problems with my charging system not working. I have a 3G alternator upgrade that I installed last year, and worked great for a while. But at the end of last summer I started having problems. When I started it up, it would run off the the battery for a couple miles and then outta nowhere the alternator would finally turn on. And now I cant get the alternator to kick on at all. Also the my radio's not working, dont know if the problem is related or not. Any help would be great guys. Thanks alot.
-Mark

 

[HISSIN50]

I would check the ignition switch. The radio thing and the fact that the alt is delayed in kicking on is why this is my crude first guess.

Does the battery light work, and ever come on (during the time out, or any other time)?

The alt needs to receive a 12 volt signal from the ignition switch in order to function properly. If the ignition switch is not providing this signal, a good alt wont work.

Any other info you can provide will help the smart folks in here to help you.

Good luck.

 

[Mizark347]

yes, during the time out the battery light comes on. so you guys think its the ignition switch, not a problem with the alternator? Any more responses would be appreciated.

 

[Mizark347]

I still cant figure this out. I changed the ignition switch and still nothin. I dont see how my alternator would only last a year. should i pull it out and get it tested?

 

[jrichker]

How it works:
The green wire is the ignition on sense feed to the regulator. It supplies power
to the regulator when the ignition switch is in the run position. Turn the
Ignition switch to off, and the sense voltage goes away, the voltage
regulator shuts off and the alternator quits making power.

Troubleshooting: Look for 9-12 volts on the green wire at the alternator. Use a safety pin to back probe the green wire. Make the test with the engine running at a fast idle.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-90 wiring and lots more…

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/88-91eecPinout.gif

Diagram courtesy of Tmoss and Stang&2birds.

 

[Mizark347]

OK, Im getting 12 volts at the green wire that plugs into the regulator. However, I am not getting any power from the white and black 18ga wire from the part that plugs into the alternator, nor from the part that plugs into the regulator. Should I be? I also forgot to mention the battery is in the trunk. Thanks Jrichker

 

[jrichker]

The yellow wire is the one to look at since it is the voltage regulator power feed. It should always have the same voltage as the alternator power output wire. If it doesn't, the fuse link in it has blown.

 

[Mizark347]

The white and black wire is the only wire that doesnt have power running through it. The yellow wire has power.

 

[Mizark347]

What does the white pig tail wire do?