Stumped and Need Help

Vettn71 · Nov 22, 2014

1995 GT, all stock

Week before last when driving to work I heRd my drive belt squeal, smelt rubber and my voltmeter went down to the "N". After a mile or two it started charging again. After work I had no output from the alternator, so drove it home and pulled it. The bolts holding on were loose, allowing the alternator to twist. The smog pump was making noise, so I put both on last weekend. I noticed the single pin connector to the alternator was broken and loose, so I replaced it. Started it up and drove it to get gas. Full voltage, about 14.4 volts.

the next morning when I. Started it there was no output. I figured the alternator failed and put alternator number 2 on. The voltage slowly rose to about 12.7 volts, but when I put the headlights on,it dropped to 11.7 volts and kept dropping. I jacked the car up and checked tightness of all wiring back to the starter, as well as to the fuse box. Al good.

I went by a shop I deal with and he said it was either the alternator (again) or a wiring problem. He said to pull the alternator fuse in the engine compartment and check for voltage on it. If I had voltage there it was probably the alternator. I pulled the fuse and had full battery voltage on it.

I put put alternator number 3on and also changed the voltage regulator connector (3pin connector). Nothing. The battery voltage slowly drops as the car runs. I'm pretty stumped here and could use some help on what the problem may be

BTW I used Western Union splices for all connection, twisted the wires, soldered then shrink wrap.

TIA. Jim

Vettn71 · Nov 22, 2014

Did some more checking. I don't have voltage to my green/red wire on the alternator. My understanding is that this wire turns the alternator on and comes from the voltmeter. There's supposed to be. 500 ohm resistor parallel to the meter, but the only resistor I see(510 ohm) is on the other side of the instrument panel. Is that the correct one to check?

jim

mcglsr2 · Nov 22, 2014

Do you know for a fact that the alternators are good? I would suggest taking all of them to Auto Zone or equivalent and have them tested (should be free).

Not sure what you are talking about regarding the "voltmeter" - the only resistor I know of is connected to the charge indicator light (the 510 ohm one) - this is there because that circuit is necessary for the alternator to work properly, and if the light bulb goes burns out it doesn't kill the circuit - thus the resistor (this resistor is located behind the instrument cluster).

The alternator circuit is actually pretty straightforward. There's only a handful of things that could be wrong. The most typical and common is the regulator on the alternator goes out. This essentially takes out the alternator. Having the alternator tested will confirm if your alternator is good or not. Other than that, there's not much else that could be wrong. Here's a list of items that could be bad:

Alternator/regulator is bad
Fuse in engine bay is blown
Instrument Panel fuse is blown
Fusable links feeding alternator are bad (they come out of the engine bay fuse panel, there are 2 of them, and they feed into a single wire that goes to the alternator
If all of the above are good to go, and it's still not charging, then you have an open circuit somewhere in the alternator wiring - either in the power wires to the alternator or in the wire that runs to the charge indicator lamp

Good luck on your hunt!

Vettn71 · Nov 22, 2014

I've had each alternator checked when I returned them and they check out good. They use Motorcraft regulators. On my95 GT I don't have a light, just a voltmeter. Tomorrow I'll check the resistor and see if I have voltage across it and what it's resistance is. From the schematic I have it looks like there's nothing between the fuse and the alternator except the resistor/voltmeter.

i did check the fusible links, fuses (engine compartment and inside) and voltage at the D plug.

Thanks for the suggestions

Jim

mcglsr2 · Nov 22, 2014

Vettn71 said:
I've had each alternator checked when I returned them and they check out good. They use Motorcraft regulators. On my95 GT I don't have a light, just a voltmeter. Tomorrow I'll check the resistor and see if I have voltage across it and what it's resistance is. From the schematic I have it looks like there's nothing between the fuse and the alternator except the resistor/voltmeter.

i did check the fusible links, fuses (engine compartment and inside) and voltage at the D plug.

Thanks for the suggestions

Jim

By voltmeter, you are referring to the voltage gauge, yes? And you do have a light - unless you removed it? It's called the charge indicator lamp. The voltage gauge has absolutely nothing to do with any of this. All it does is get power from a fuse, and display the car voltage. That's it. It's not hooked up to your alternator at all. What *is* hooked up to your alternator are those fusable links I mentioned, the charge indicator lamp (with the resistor), and the power wires. There's also the rectifier (which is the voltage regulator), but that's essentially built in to the alternator. That's it. If your voltage is low, it has to be one of those 3 things causing it.

--OR--

You have a short somewhere and it's pulling down your voltage. Here's a quick test: unhook the alternator completely. Run the car off the battery, with no lights, no radio, nothing power on. Just start the car and let it idle. Measure your voltage - should be around 11.8 or so. Put on your headlights. The voltage should drop, but not tremendously. If your voltage plummets, there's a short in the lights wiring. If lights are good, turn them off and try turning on other things one at a time: radio, a/c, etc. and measure voltage each time. If the voltage always stays fairly good and doesn't drop significantly, the issue is something with your alternator, refer to the 3 things I mentioned above. If, on the other hand, you are still dropping tons of voltage, you have a wiring problem, most likely a short, and this has nothing to do with your alternator.

Note: for the above, to measure your voltage, just use the two terminals on the battery. Don't bother with other wiring just yet. Just go across the two terminals with your Multimeter. As you put a load on the battery (i.e. you turn on your head lights), you will see a drop across the two terminals.

FWIW, I have a 95 GT, I am referring to the factory manual (I have the honest-to-god paper factory manuals, not google-searched manuals), and I have replaced my instrument cluster completely (including all the idiot lights which includes the charge indicator lamp [and it's resistor]) with aftermarket gauges & lights; so I should have some familiarity with your car, unless you have changed things drastically?

Vettn71 · Nov 23, 2014

Round 2 this morning. Yes, I do have a battery/charge light, but I don't ever remember it being on.. That's why I thought I didn't have one. Pulled the instrument cluster and tested the bulb and resistor, which both checked out. I looked at the connections on the cluster and noticed there were two of the copper strips touching. Using brush on super glue I put a dot on the strip that was loose. I used the brush on because it has a 15minute set time, which would give me time to apply, position and hold without gluing my fingers to it. Started the car and was back to charging again.

i appreciate your patience and help on this, mcglsr2.

I pulled my steering wheel to change it out (grey to black) and my THEFT light is now on steady. Doesn't blink, just is on all the time, even when the ignition is off. Doesn't seem to affect the car? Seems really odd. Any ideas or should I not worry on it?

TIA

Jim

mcglsr2 · Nov 23, 2014

Sure thing man. Glad you found the problem, looks like it was a short then.

Not sure about the theft light. My car didn't come with one, so I didn't have to deal with it. Let me do a little looking, and I'll get back to you. The car starts and runs fine with the light on solid? If so, the only concern I'd have at this point would be the light staying on 24/7 and draining the battery - granted it would probably take quite a while for it to really drain. I'll do some research and get back to you.

Vettn71 · Nov 23, 2014

I pulled the bulb until an get time to look at it. Drove the car some; runs fine, so it might be another foil strip.

Thanks for the help

jim

mcglsr2 · Nov 23, 2014

Alright, I did some research in the manual regarding the anti-theft light being stuck on. The manual says that after arming the anti-theft system, the light will stay on solid for 30 seconds and then turn off. If the light stays on all the time, the manual says to do this:

ENSURE ALARM SYSTEM IS RESET

Arm the anti-theft alarm system
Within 30 seconds, insert door key and turn to unlock position
Does lamp turn off?
If YES, you are DONE - the system is OK
If NO, see below

CHECK FOR SHORT

Disconnect anti-theft alarm control connectors
Does lamp turn off?
If YES, you must replace damaged alarm controller then retest the system, starting with section above (in other words, your module is broken)
If NO, there is a short; service circuit 343 (see blow) for short circuit. Fix then retest, starting with section above

Circuit 343 is the Dark Blue w/ Light Green stripe wire that goes from the anti-theft indicator bulb to the anti-theft controller module. The control module essentially grounds this wire, which then turns on the lamp (the lamp has a hot feed). So most likely, this wire is being grounded against something (assuming your module isn't bad). It's quite possible it's the same issue where the foil/copper connectors are touching again.

Vettn71 · Nov 24, 2014

Aaaaaargh!! I bet it's another foil strip in the IC. I just lost my left turn signal bulb. I'm going to have to pull this again and go over each and every strip. Thanks for the head up on this. It will help a bunch

jim

mcglsr2 · Nov 25, 2014

Vettn71 said:
Aaaaaargh!! I bet it's another foil strip in the IC. I just lost my left turn signal bulb. I'm going to have to pull this again and go over each and every strip. Thanks for the head up on this. It will help a bunch

jim

Sure thing!

So what's going on with your connectors? Is the issue the place where the plugs connect on the back of the instrument cluster? I have not heard of anyone running into this same issue as you (but then again, I most certainly haven't seen it all...). Is there a lot of heat or some kind of weird wear going on back there?

NXcoupe · Nov 25, 2014

The voltmeter or at least the IP wiring does have something to do with the alternator power. Found that out in a fox body when I switched to a different year cluster and lost charging. Went back to previous cluster and it charged fine. Figured out by looking at the wiring diagrams they move that voltage wire around on the plug year to year, which doesn't affect the sn95 platform but does illustrate the IP wiring does affect the charging. Maybe it needs to ground through the alt light? I'm leaning that way since I can't recall the wiring diagram in my head right now.

mcglsr2 · Nov 25, 2014

NXcoupe said:
The voltmeter or at least the IP wiring does have something to do with the alternator power. Found that out in a fox body when I switched to a different year cluster and lost charging. Went back to previous cluster and it charged fine. Figured out by looking at the wiring diagrams they move that voltage wire around on the plug year to year, which doesn't affect the sn95 platform but does illustrate the IP wiring does affect the charging. Maybe it needs to ground through the alt light? I'm leaning that way since I can't recall the wiring diagram in my head right now.

Nope, the voltage gauge has NOTHING to do with the alternator. If you lost charging when swapping clusters, it's because the charge indicator lamp wire got changed. The charge indicator lamp has everything to do with the alternator. The voltage gauge is just simply a gauge that measures voltage on the car power wires. That is it. It's gets power from a fuse, and it goes to ground. Period. You can remove it if you want. The car will run fine, and charge fine. Trust me. I have studied the factory manuals. I have completely replaced my stock voltage gauge with an aftermarket one. I do not run a single stock gauge. Believe me when I say I have looked into this

FWIW: I have a 95 GT, and this is what I am referencing. Newer model years might be different, but I doubt it.

Edit: Yes, the IP wiring does interact with the alternator - as I mentioned above and in a previous post, it's the charge indicator lamp. That's the guy. I never said that the IP wiring didn't have anything to with the alternator; quite the contrary, actually

Vettn71 · Nov 25, 2014

The issue with my IP is that the foil strips are starting to lift from the plastic "circuit board". It looks like it's an age related thing. If the touch,game over for that function.

As far as the alternator circuit, it runs from a 20A fuse in the passenger compartment meant fuse panel, through the battery light on the IP and then straight to the alternator. When the foil strips touched it shorted the alternator circuit out. When I cleared the short the alternator started working

jim

NXcoupe · Nov 25, 2014

mcglsr2 said:
Nope, the voltage gauge has NOTHING to do with the alternator. If you lost charging when swapping clusters, it's because the charge indicator lamp wire got changed. The charge indicator lamp has everything to do with the alternator. The voltage gauge is just simply a gauge that measures voltage on the car power wires. That is it. It's gets power from a fuse, and it goes to ground. Period. You can remove it if you want. The car will run fine, and charge fine. Trust me. I have studied the factory manuals. I have completely replaced my stock voltage gauge with an aftermarket one. I do not run a single stock gauge. Believe me when I say I have looked into this

FWIW: I have a 95 GT, and this is what I am referencing. Newer model years might be different, but I doubt it.

Edit: Yes, the IP wiring does interact with the alternator - as I mentioned above and in a previous post, it's the charge indicator lamp. That's the guy. I never said that the IP wiring didn't have anything to with the alternator; quite the contrary, actually

should have slowed down and read my post carefully before getting your feathers in a ruffle, lol. Yeah, volt gauge just reads off the power wire coming from a cluster of power wires under the dash in the dash wiring. The IP light is the part that will cause it to stop charging as you said. But that's where he found the solder stripes peeling and not making contact. Just tossed out my experience, well because I can.

mcglsr2 · Nov 25, 2014

NXcoupe said:
should have slowed down and read my post carefully before getting your feathers in a ruffle, lol. Yeah, volt gauge just reads off the power wire coming from a cluster of power wires under the dash in the dash wiring. The IP light is the part that will cause it to stop charging as you said. But that's where he found the solder stripes peeling and not making contact. Just tossed out my experience, well because I can.

No feathers in a ruffle here. I was just going off of the first line in your post: "The voltmeter or at least the IP wiring does have something to do with the alternator power. " And then: "Figured out by looking at the wiring diagrams they move that voltage wire around on the plug year to year," Yes, I did read through all of it. Sorry if I came across rude or anything, wasn't trying to. I had just explained in a previous post that the voltage gauge had nothing to do with it, and then you started your post that way. If you had just said "The IP wiring has something to do with it" then I wouldn't have had anything else to say. But I read your post as "hey, well, the voltage gauge does have something to do with it, or if it doesn't, then something in the IP cluster does." And like I said, I explained it in a previous post, so I felt like you didn't read my post. Whatevs, I'm not upset or anything, sorry if I came across gruff. I probably just read your post wrong.