charging problem

Are you using a 2G alternator? What are the voltage values you see at the regulator?
After a swap like that, it could be that your I terminal is not hooked up, or that A is not connected to battery voltage.

Good luck.

Tools needed: DVM (Digital Multi Meter) or multimeter, 1/2" wrench, 2 safety pins.
The safety pins are used to probe the wiring connectors from the wire side.
Make sure you know how to correctly use a DVM or multimeter.

Resistance checks:
Do not make resistance measurements with the battery ground lead connected. You will get
incorrect results and possibly damage the DVM or multimeter
Do not test the white/black wire at this time.
With the battery ground cable disconnected from the battery, use an ohmmeter to check continuity
on the wires. Turn the key to the Run position and place one ohmeter lead on the positive
battery cable and the other on each of the wires.

EDIT: All wires should read less than 1.5 oms, except the lt green/red wire, which should be 100-500 ohms

Testing the white/black wire:
Use the safety pins to probe the wiring connectors for the white/black wires or
disconnect them and probe the connector from the front side. You shoul see less than 1.5 ohms.

Voltage checks:
Carefully re-connect the battery cable postive termnial to the battery at this time.
Make sure that it is clean and tight
With tht stock alternator, you should see battery voltage (12 volts or more) on the black/orange,
yellow/white and lt green/red wires with the ignition switch in the run position. All measurements
are taken at the alternator.

No 12 volts on the black/orange wires - fuse link probably open
No 12 volts on lt green/red wire - dash indicator burned out, and 500 ohm resistor open circuited
No 12 volts on yellow/white wire - fuse link probably open

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/ Everyone should bookmark this site.

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

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

droptopfpm said:

dash indicator? do you mean the gauge? and if so it isnt working also any
way to just wire this thing up to work?

Click to expand...

The dash indicator is the battery warning light.

I recommend that you study the diagram I attached to the post, and consider how everything is wired together.

1.) Does the battery warning light turn on when your turn the key to Run without the engine running?
If it does, then it is not a problem.

2.) Did you actually measure the voltage on the lt green/red wire?
If it does show 12 volts and the dash indicator lamp does not turn on, the light bulb is burned out
or loose in the socket.
If there is no 12 volts, then there are problems in the wiring.

A bad needle placement would not affect charging. It would be nice if it was that easy. Instead of buying an expensive upgraded alternator, we could just move the gauge's needle.

The chances of an issue with the resistor in parallel with the amp bulb is very unlikely IMHO.

Do your testing as JR outlined to figure things out quickly, rather than wasting time going off of bad testing (ensure your initial testing was correct before going down one road for too long). I learned that the hard way a long time ago.

Good luck.

Until you measure the voltage or resistance of the lt green/red wire, you cannot be sure it is the problem.
Do the testing first, then use the test results to guide you to what's broken instead of guessing.