I NEED HELP, CHARGING PROBLEM

[green87]

This is what was done

New Clutch and all the do dads that go with that.
Everything worked fine

Started over heating. Replaced Radiator, fan, and thermostat, still over heating, FORD replaced the heatercore... all is good, so i think.

When i get it back, speedometer isnt working. They claim its not them...whats expected right? Next morning wont start. Through slaving over the motor this is what i have now replaced.

New Battery Cables
New Battery
New Alt.
New Plugs at the Alt.
New Fuseible Link
New Starter Switch Soleniod

Checked all the fuses... good.


Im out of ideas. And i need some help. I noticed there were some other people that experienced this problem once their heater core was replaced but none that i found had the fix on the thread. Please some one help me out!

Thankx


87 5.0

 

[HISSIN50]

Does it not turn over or not catch?

 

[green87]

it turns over and starts up, but you have to have charged the battery, then while your driving you can just watch the bat. meter fall till finally it shuts off.

 

[HISSIN50]

If you don't have a DMM, have the alternator either dynamically or bench tested. If the bench test passes, test the regulator and the rectifier plug for proper values.

 

[green87]

ok, well i dont know what DMM is? And does bench test mean take it out of the car? This is the 5th Alt. that i have put in it. and if im not mistaking isnt the regulator inside the alt. on this model? i dont know awhole lot about this. but what i do know i have tried. also is the rectifier the smaller plug? that plug and that other on the alt have been replaced. thankx alot for your help though, i will do all this in the morning. anything else you can suggest so maybe i can try it right afterwards if non of this is the case?

 

[jrichker]

Alternator troubleshooting for 86-95 5.0 Mustangs:

Do all of these tests in sequence. Do not skip around. The results of each test depend on the results of the previous
tests for correct interpretation.
Changes in wiring for a 3G alternator are in red

Engine off, ignition off, battery fully charged.
1.) Look for 12 volts at the alternator output. No 12 volts and the dark green fuse link between the orange/black
wires and the battery side of the starter solenoid has open circuited.
3G alternator: Look for 12 volts at the stud on the back of the alternator where the 4 gauge power feed wire is bolted.
No voltage and the fuse for the 4 gauge power feed wire is open or there are some loose connections.
2.) Look for 12 volts on the yellow/white wire that is the power feed to the regulator. No 12 volts, and the fuse link
for the yellow/white wire has open circuited.

Engine not running, ignition on, battery fully charged.
1.) Alternator warning light should glow. No glow, bulb has burned out or there is a break in the wiring between the
regulator plug and the dash. The warning light supplies an exciter voltage that tells the regulator to
turn on. There is a 500 ohm resistor in parallel with the warning light so that if the bulb burns out, the regulator still gets
the exciter voltage.
Disconnect the D connector with the 3 wires (yellow/white, white/black and green/red) from the voltage regulator.
Measure the voltage on the lt green/red wire. It should be 12 volts. No 12 volts and the wire is broken, or the 500 ohm
resistor and dash indicator lamp are bad. If the 12 volts is missing, replace the warning lamp. If after replacing the warning lamp,
the test fails again, the wiring between the warning lamp and the alternator is faulty. The warning lamp circuit is part of
the instrument panel and contains some connectors that may cause problems.

2.) Reconnect the D plug to the alternator
Probe the green/red wire from the rear of the connector and use the battery negative post as a ground. You should see
2.4-2.6 volts. No voltage and the previous tests passed, you have a failed regulator. This is an actual measurement taken
from a car with a working electrical system.

Engine running, Ignition on, battery fully charged:
Probe the green/red wire from the rear of the connector and use the battery negative post as a ground. You should see
battery voltage minus .25 to 1.0 volt. If the battery voltage measured across the battery is 15.25 volts, you should see 14.50 volts

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 Mustang FAQ - Engine Information 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

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pinout
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

 

[green87]

thanks, im taking my dash out tomorrow, bc when i got it back from FORD the speedometer wasnt working either so i bet he didnt hook up something else which is why the Alt. light, and Bat. light dont turn on also..... which could be my problem. i will let ya know if that is the fix!

 

[Saleen0679]

That's likely to be your problem. When the Charge indicator circuit is not connected the alternator will not charge the battery.

You don't have to take the dash out to work on the instrument cluster connections.

 

[green87]

how would i get to that with out taking the dash out?

 

[Saleen0679]

Somewhere on the forum there is a detailed write-up for the instrument cluster.

You really only need to remove a couple of switch assemblies, the cluster bezel, and maybe some trim pieces to gain access to the instrument cluster. In a nutshell:

Removal

1. Disconnect battery ground cable.

2. Remove switch assembly on RH and LH sides of cluster assembly.

3. Remove two upper and three lower retaining screws from the instrument cluster trim cover. Remove the trim cover.

4. Remove four retaining screws from instrument cluster to panel.

5. Pull the cluster away from the instrument panel. Disconnect the speedometer cable by pressing on the flat surface of the plastic connector (quick connect), located behind the instrument cluster.

6. Pull the cluster further away from the instrument panel. Disconnect the two cluster printed circuit connectors from their receptacles in the cluster backplate.

7. Remove cluster.

CAUTION:
If gauges are being removed from the cluster assembly, do not remove the gauge pointer; magnetic gauges cannot be recalibrated.

 

[green87]

thanks, i will give it a try

 

[green87]

ok so i got the cluster out, gotta give it to ford, when i pulled it forward my speedo cable just fell off and in one of the plug in the circuit board was all screwed up... like really??? so now i am trying to hunt down a instrument cluster that has a good circuit board.... anyone looking to get rid of theres???

87 5.0 w/ 140mph speedo