The wiring gods must be angry with me

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The wiring gods must be angry with me

March 13, 2008, 09:22:06 PM

The DD stranded me twice in two days. The electrical system isn't charging, so any insight would be greatly appreciated. Here are the steps I've taken:

The alt, voltage regulator, and a fusable link were replaced about 10 months ago. On two separate occasions, I've had the battery and alt tested - each passed. I've replaced the VR twice. While the car was running and the relevant tested components installed, we checked the voltage output.

The battery tests ~12.5V at rest. With the engine running, voltage tests in the mid-11s at the battery, alt, and solenoid. At one point, I wiggled the wiring harness near the PS pump and the voltage jumped to 12.5V. I've squeezed, pulled, and wiggled the triplet of fusable links near the solenoid, no noticable change in the voltage. The factory charging wire (black w/ orange stripe) was frayed, that's been replaced by a 4 gauge cable running to the solenoid.

In desperation, I rewired for a 3G and swapped in a new alt for a 95 Mustang. We tested it after swapping pulleys. After installation, no change in the system output.

Then something else happened. I tried to turn off the car, and it kept running. Someone suggested a bad ignition switch might be causing the charging problem, so today I installed a new switch. The new switch has no effect - still discharging and the car continues to run, even with the ignition in the "off" position.

If you've made it this far, do you have any suggestions (besides taking a flamethrower to it)?

The wiring gods must be angry with me

Reply #1 – March 13, 2008, 10:42:00 PM

put a volt meter on the battery while the car is running and you should be getting 13+. If not, then it's a bad alt, reg, or wiring.

The wiring gods must be angry with me

Reply #2 – March 13, 2008, 10:44:05 PM

Tested voltage at the battery at rest and running. 12.5V at rest, ~11.5V running. I tested the original alt and the new alt, replaced and removed the VR.

That leaves the wiring, but where?

The wiring gods must be angry with me

Reply #3 – March 13, 2008, 10:49:57 PM

Make sure your bat. cable is good and start checking from there.
could be a broken wire in there somewhere.
That would be a starting place

The wiring gods must be angry with me

Reply #4 – March 13, 2008, 10:51:21 PM

Forgot to mention I checked the grounds and the cables.

The wiring gods must be angry with me

Reply #5 – March 14, 2008, 12:53:09 AM

Hold a hacksaw blade by one end and touch the other end to the laminated part of the alternator.
Ignition off, no magnetisim.
Ignition in run (don't start) you should feel magnetism. Voltage from the ignition switch should be on the LG/R wire to the I terminal of the voltage regulator.
Do you have an alternator idiot light? Is it on with the ignition in run?
The voltage to the I terminal of the regulator comes through the light bulb and/or the shunt resister across the bulb.

The wiring gods must be angry with me

Reply #6 – March 14, 2008, 01:58:27 AM

well, there is a couple other things but i gotta think about this one. car stays running after you turn it off.

The wiring gods must be angry with me

Reply #7 – March 14, 2008, 07:36:14 AM

Ignition switch???????

The wiring gods must be angry with me

Reply #8 – March 14, 2008, 08:15:39 AM

I second the question about the alt/batt light. Does it light up? with the KOEO?

The car staying running is an odd one....

The wiring gods must be angry with me

Reply #9 – March 14, 2008, 08:36:14 AM

When you replaced the ignition switch, did you replace the switch or the key cylinder? I know it seems a stupid question but a lot of people think they're the same thing. Also when (if) you replaced the switch, did you replace the connector and harness end? They often burn up when the switch fails.

The wiring gods must be angry with me

Reply #10 – March 14, 2008, 11:02:52 AM

buttstuffog gauges, no warning light. The white/black stripe wire from the alt (STA) dead ended in the wiring harness. The original VR socket and plug both had three contact points, "I" wasn't used. For the 3G conversion, I jumped the "S" to "A" point in the VR plug.

Yes, I replaced the switch, not the cylinder lock. No, it's not a stupid question. I didn't replace any wiring in the steering column. The plug to the switch didn't appear bad to casual observation.

Also, just before this key-out, engine-running senario, I noticed that a couple of the system sentry lights stayed "on" the last time I was able to turn off the engine with the key.

The wiring gods must be angry with me

Reply #11 – March 14, 2008, 12:25:16 PM

Quote from: t3skidoo;209120

buttstuffog gauges, no warning light. The white/black stripe wire from the alt (STA) dead ended in the wiring harness. The original VR socket and plug both had three contact points, "I" wasn't used. For the 3G conversion, I jumped the "S" to "A" point in the VR plug.

Ok let me see if I follow this correctly. You originally had an external voltage regulator on a car with an ammeter and no battery light.

The I input to the old regulator was unused..that is correct.
The Sta output of the old alternator was unused..that is correct.

You jumpered the S to A in the old VR socket. I have a problem with that but we will talk about that later.

The important thing is how do you have the new 3g alternator hooked up.
You have the alternator part with a B+ and S terminals.
You have the internal regulator part with A,I and S terminals.
How are they hooked up?

The wiring gods must be angry with me

Reply #12 – March 14, 2008, 01:58:31 PM

Quote from: softtouch;209131

Ok let me see if I follow this correctly. You originally had an external voltage regulator on a car with an ammeter and no battery light.

correct

Quote from: softtouch;209131

You jumpered the S to A in the old VR socket. I have a problem with that but we will talk about that later.

The important thing is how do you have the new 3g alternator hooked up.
You have the alternator part with a B+ and S terminals.
You have the internal regulator part with A,I and S terminals.
How are they hooked up?

I was using two docs
http://rothfam.com/svo/3g/
and
jcassity's 3g diagram

Mine's wired as the illustrations in the first link except -
for the plug, only the two inner points are jumpered
for the alt, I didn't connect anything to the A terminal

The wiring gods must be angry with me

Reply #13 – March 14, 2008, 04:47:01 PM

That writeup would have worked if you had the indicator light system as shown in the diagram.

The ammeter system is different.

Did you disconnect the old output wire and install a new 8ga wire. If so where did you run it to?

If you use the old output hookup we can fix this pretty easy and end up with a ammeter that still works.

The wiring gods must be angry with me

Reply #14 – March 14, 2008, 07:11:32 PM

If by "output wire" you mean the black w/ orange stripe wire that runs to the solenoid, it was frayed; that might have affected the voltage output fluctuation when I wiggled the harness.

I replaced the B/O wire with a 4 gauge cable and a 100A fuse. The fuse mounts to the alt, the cable runs from the fuse to the + terminal of the starter solenoid.