I am working on a 1991 Camaro that I bought with a partially completed 5.3L LS swap done to the car.
Somewhere along the line either previous owners or previous "mechanics" have really hacked up the wiring.
I have many cut wires all over the place as well as various connectors just hanging loose.
This connector is under the left side of the dash near the fuse box. There is a thick purple and a thick yellow wire going into the connector.


Loose connector under extreme left side of dash by fuse box.
Then there a a whole BUNCH of loose wires coming out of the junction box under the hood to the left of the brake booster.


Four thick wires, two red and two pink, or maybe a light purple and a pink. Then a whole bunch of thinner wires with colors listed below.
The thinner wires in this bundle are as follows:

Lt Green
Lt Blue
Lt Purple
Pink
Tan
Dk Blue
White (quantity 2)
Black/white stripe
Dk Green (quantity 2)
Brown (may have been wired to multi-plug on Alternator)
Gray

Down under the car hanging loose off the LS starter are two thick red wires on the main starter terminal and a blue wire off the starter solenoid.
I was hoping that the two thick red wires from the starter might connect up to the two thick red wires over on the bulkhead connector in the above picture.
I have not yet been able to figure out what wire on the column might be the right wire to connect up to the starter solenoid.
I pulled the center console apart to look for any wires that might be connected to the original neutral safety switch but there was no wiring connector on that NSS in the console next to the shifter.
I do think when I turn the ignition key to the on position one of the thick pink wires coming off the bulkhead connector gets connected to one of the thick red wires in the same location so that might be switched power.

Any help identifying any of this mess of wires would be most appreciated.

 

Buy a factory service manual, then identify them one by one and write what they do on painters tape with a sharpie.

 

The yellow/purple are for the neutral safety/clutch interlock. If it's a stick car it hooks to the switch on the clutch pedal. If it's an auto car it should be wound up and not used. The wires coming out of the c100 will all need to be traced and labeled. You'll need a manual or pin out for your year car. It's all ways fixable, just not enjoyable to have to do.

 

Fat wires:

• Kinda stupid to cut those. The 2 reds and the purple in particular. Butt hay, whatever Stimpy did, is done now, and it's too late.
• The 2 red are the battery feeds into the cabin. They got their power from the 2 fusible links at the starter.
• Pink is ignition from the ign sw to the distributor. AFAIK most LS swap wiring will use this as the main ign feed to the LS ECM etc. Details of that will vary widely.
• Purple is the starter solenoid from the neutral/clutch safety sw and ign sw.

Thin wires:

• Blk/wht is ground to/from various underhood things mostly related to the ECM. At one point it goes to the engine (back of the pass side head), but also to various other things such as coolant temp sensor.
• 1 of the dk grn is the temp gauge. Goes to the sending unit.
• 1 of the white is the tach. That will need to be driven somehow from the swap ECM. The car originally had a distributor which gave 4 pulses per engine rev if the car had a V8 or 3 per rev if it was a 6-cyl. Somehow or other you'll need to get that signal from the swap ECM to drive your factory tach or typical aftermarket one.
• Tan is probably the oil pressure gauge. If so, goes to that SU.
• Some of the others are for the wiper motor.

As said, you'll probably need a copy of the FSM to get much farther than that, other than by tracing the cabin side of them.

 

Thanks for that info sofakingdom
That helps a lot.
I did go to the local main library yesterday and make copies of LOTS of pages from the factory 1991 shop manual.