I put a meter to the wires leading to the harness where I clipped them and one wire read 12 volts when it was in the "run" position and the other wire had no voltage. I need to know which one to connect them to.

 

The one on the right should go to the wire that is ign power from secondary fuse 10 amp

To be more exact,

The terminals on your alternator plug are , starting with the large terminal, S,,, F,,,L,,,P

Our cars only hook up F and L

the letters are on the alt and should be on the plug

F goes to secondary fan relay fuse in the under hood fuse box and should be powered when ignition is on ( test to be positive by pulling fuse with test lamp hooked to the wire)

L goes to the instrument cluster

 

So it's the F pin. I guess I could test it by pulling the fuse and check for voltage? I'd assume if it was wired wrong it would screw something up?

 

Here's the schematic.....

http://www.goldsswagon.com/diagrams/impala_charging.pdf

EDIT - Just meter the wires back to Fuse 8 and Fuse 11 and figure out which wires goes to Pins F & L in the Connector. Check those fuse locations in the Schematic, it looks like Fuse 8 is in the Under Hood Fuse Panel and it looks like Fuse 11 is on the Dash Fuse Panel.

 

Quadruple checked to make sure I wired it correctly, plugged it in and started it. It ran for about 1 second then shut off. Now it won't start. The starter is spinning, all the fuses are good under the hood except the 40 amp primary cooling fan fuse. Would that keep it from starting?
I disconnected the battery to see if that would work but no go. I can hear the fuel pump prime so it's not that. I did nothing different except hook up the new connector. It would run without the alternator plugged in before I wired in the new harness. This sucks. I'm really beginning to take this as a sign I shouldn't keep it.

 

If you hook them up backwards it will fry the voltage regulator.

As to why the car will not start. Did you replace the primary fan fuse?

 

I will replace it. It used to run without it. It's had a chronic problem blowing the primary fan fuse. Where is the voltage regulator located? If it's inside the alternator shouldn't it start if I disconnect it? That didn't work either.

 

Replaced the primary cooling fan fuse. Still won't start. Guess I'll dig deeper. Ugh....

 

Update

Ok, after looking at all the other "won't start" threads, I did some digging and found NOTHING wrong and there should be ZERO reason for it not to start. I checked all the fuses and they were all good. Disconnected and reconnected harnesses, swapped out an old alt I had and reinstalled the old one. Pulled the coil wire/s off and put them back on. I figured I'd try to start it and sure enough it did. No idea what was wrong. It started with the old alt on so I put the other back on and tested the voltage. Alt and battery are good. It did cut off after 30 seconds the first 2 times I started it but it's been running for about 5 min or so. At least she's running now. Time to scratch it off the list.

 

not running... AGAIN

Well, I went out to start it to let it run during all the snow and it started fine. The next day, I went out to drive it to work and it cranked and would not start. Long story short, I need to know how to test the coil and ICM. Fuses are fine, I'm getting fuel but need to test spark.

 

Well, I went out to start it to let it run during all the snow and it started fine. The next day, I went out to drive it to work and it cranked and would not start. Long story short, I need to know how to test the coil and ICM. Fuses are fine, I'm getting fuel but need to test spark.

with a fuel pressure gauge do the complete fuel pressure test. how much fuel in the tank ? the other simple cause may be a bad ECT. this is on the water pump ..a bad sensor or connector will cause a poor or no start condition ..also will not throw a code in most cases as well as the fuel delivery system being the cause.

with this all checked out good sure could be the ignition system .

 

Running again

I got a spark tester from Harbour Freight and had no spark. I could smell fuel on the plug that I pulled and I could hear the pump prime so I knew it wasn't a fuel issue. I phoned a friend who had a spare coil and ICM and plugged his in. She fired right up. Not sure if it was the coil or ICM but both were replaced. My guess is the coil. It was a MSD Blaster coil.

 

If you are installing a new ICM, or reinstalling the original ICM, use the white heat sink paste from Radio Shack, not the dielectric grease. If you use the grease, you will fry the ICM.