alternator & VR problems

hey guys - more problems need some help

Few days ago had a dead battery. Tested at 11.4 volts. Took it to NAPA - they said a bad cell. Put in new battery. Within a week - dead battery.

Here is what I did:

1. Cleaned battery terminals and posts

2. Charged battery and then test battery across post - got 12.4 volts

3. Started engine and tested bettery across post - got 12.4 volts = not charging

4. Turned off Engine and removed ground cables from battery

5. Used test light from negative post to ground - test light did not come on = no battery drain

6. Reattached battery cables

7. Unplugged VR and plugged it to temp replacement VR that was grounded to negative post of battery with jumper wire/alligator clips

8. Started engine and tested battery across post - got 12.4 volts

9. Followed same process with another VR and got same results.

10. removed battery cables and alternator - noticed broken wire from stud - broken wire

11. fixed wire and reinstalled alternator and battery cables.

12. Tested with old VR and the other two VR's and got same 12.4 volts reading with engine running

13. Installed used alternator and performed tests with the same three VR's and got same 12.4 volts reading

14. I did noticed there was some corrosion on the plug that goes into the VR after all the previous steps above. One of the wires broke off from the plug at the "A" that goes into the VR. It was yellow wire plugged into same terminal of another yellow wire. It goes to the "thing" that is supposed to keep the humm sound out of the AM radio i think.

VR broken wire -VR broken wire

corroded plug - corroded plug

I borrowed the two VR's and alternator from local shade tree mechanic. He said they all worked when they were removed from other Fords.

I'm not sure how to use multimeter as to test which terminals on alternator or VR other than what I did above. I have read other threads but still dont quite get where to put the multimeter leads on which terminals to do the testing.

I thinking of getting a plug from junkyard ford to see if that is the culprit. Did I miss anything? Please Help

john

Good job..!

You're on the right track. At this point I'd have alt. & VR tested at auto parts, (it's free) just to be comfortable they're working good.

Wires on back of alt. need to make good contact as you've seen.

The VR plug is suspicious.... needs continuity fr. the corroded part on thru the wire. You can clean the plug with household "lime-a-way" using a small brush or a Q-tip., rinse & light oil.

Set voltmeter to OHMS & if you can't locate the other end of the wire...,you can stick a sewing needle into the wire just enough to test for continunity by touching meter probe to needle.

I believe the yellow wire goes to the hot side of the starter solenoid.

A white wire goes to the alt.

Splicing in a new plug for VR wouldn't hurt either.

Keep in mind those wires are brittle (esp.the insulation) & need careful handling.

HTH

B

Bully Bob said:

Good job..!

You're on the right track. At this point I'd have alt. & VR tested at auto parts, (it's free) just to be comfortable they're working good.

Wires on back of alt. need to make good contact as you've seen.

The VR plug is suspicious.... needs continunity fr. the corroded part on thru the wire. You can clean the plug with household "lime-a-way" using a small brush or a Q-tip., rinse & light oil.

Set voltmeter to OHMS & if you can't locate the other end of the wire...,you can stick a sewing needle into the wire just enough to test for continunity by touching meter probe to needle.

I believe the yellow wire goes to the hot side of the starter solenoid.

A white wire goes to the alt.

Splicing in a new plug for VR wouldn't hurt either.

Keep in mind those wires are brittle (esp.the insulation) & need careful handling.

HTH

B

Click to expand...

Check continuity through the plug. it passed. I will clean it anyway. The wire color from left to right in the pic is orange "F", green with red "S", yellow "A". To test each of these, where do I put the leads of the multimeter?

thanks - john

Green w/red goes to key switch....

Yellow to starter sol. .....

I'm showing "white" you're saying "orange" but it should go to the back of alt.

I'm hardly a wiring expert., sooooo., check me on these.... :-"

Bully Bob said:

Green w/red goes to key switch....

Yellow to starter sol. .....

I'm showing "white" you're saying "orange" but it should go to the back of alt.

I'm hardly a wiring expert., sooooo., check me on these.... :-"

Click to expand...

ON the Continuity: 2 of the three passed. The orange and yellow passed. The green with red, well it sort of passed. I checked it at the plug as it came from the firewall into engine compartment. I think I read somewhere it is paired with a brown wire at this plug to match up with the pink resistor wire from coil. It passed at the plug from firewall, but not from that point to regulator. I had one pin in the plug connector for the regulator and the other in plugs(s) by firewall.

Not sure what to tell ya fr. here....

I think there should be cont. fr. the back of key switch (green/red) to the volt. reg. thru the firewall plug & thru the volt. reg. plug.

Believe there's an attached wire fr.where it attaches to key switch to the fuse block.

Bully Bob said:

Not sure what to tell ya fr. here....

I think there should be cont. fr. the back of key switch (green/red) to the volt. reg. thru the firewall plug & thru the volt. reg. plug.

Believe there's an attached wire fr.where it attaches to key switch to the fuse block.

Click to expand...

I think I found something that may help this and the other thread I had with the coil getting hot with key on ACC.

I did a continuity test from the plug at the VR. The orange to alternator was ok and so was the yellow to stater selonoid. but the green with red was not. I did have continuity on green with red at the plug as it exits from firewall behind the fuse box on engine compartment side. On the plug from that point which is the pink wire toward the coil - no continuity. It has been cut and taped off in the engine compartment.

On other thread, that is where that green wire was spliced into the pink wire coming from coil and ran to the big stud terminal on the back of ignition switch. An aftermarket fuel gauge was spliced into green wire casuing the coil to get hot when key in ACC position. Looks like a section the ignition coil resistor pink wire was cut near the coil and cut by the plug near firewall.

So, if I reconnect the pink wire(s) with a ballast resistor(1.35 ohms) linking the pink coil wire and the pink wire from plug at firewall I should:

1. Have continuity to VR at green with red wire terminal?

2. Solve the hot coil with key on ACC (assumed spliced green wire is removed linking the pink coil wire and ignition terminal)?

3. Battery will charge assuming alt and VR are good?

Continuity from the key to the VR on the green with red striped wire is required for the alternator to work. Don't jury rig it, fix the problem. The green with red wire is the exciter voltage for the alternator.

Also I would change that plug to the VR. No matter what continuity you get from it to anything else, the contacts may be in such poor shape that they don't make contact when it is connected.

Good luck,

In case I missed something, sorry, but check for battery voltage at the F (field) wire at the regulator with the switch on. If you have voltage there, with the regulator unplugged, jump the A & F terminals in the connector. Start the engine. If the alternator's working, the amp gauge should peg out. If the amp gauge doesn't peg out, the alternator isn't working. If it does, then the regulator's bad. If nothing happens, both are probably bad. Jumping the A & F simply bypasses the regulator. One thing I learned many, many years ago with electrical stuff. If you don't know for a fact used stuff is good, don't use it. That'll save a lot of headaches.

Bad VR. Replaced it. Now I get 14.01 at the battery at idle. Thanks for help guys. Also solved a hot coil problem - I'll get to that on the "why is my coil hot" thread.

Thanks again guys,

john

Thanks for reporting back on the solution.

Good luck,