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Needing some guidance to sort and separate original engine harness.
using all the power wires and gauge wires.& Power to supply heat and ac.
Started to remove relay wires(3 relays firewall)
those were lose and torn so I started there.
Working my way down.
Not a fan of the fusable links but if they work why not?
Basically don’t want to cut the wrong thing that way everything works properly for my swap. If there’s a thread on this please share.
How should I wire this thing up properly
There’s 14 pins. 90-92 harness. I dabbed yellow on each pin. And red on the picture. Can anyone tell me why there’s no backup light pins? Does your car have to be a manual? I’m trying to complete the circuit for reverse lights from the switch in the trans. To complete the circuit.
There’s 14 pins. 90-92 harness. I dabbed yellow on each pin. And red on the picture. Can anyone tell me why there’s no backup light pins? Does your car have to be a manual? I’m trying to complete the circuit for reverse lights from the switch in the trans. To complete the circuit.
Not sure about "sort and separate" and "3 relays" and all that; sounds mostly like stuff that needs to be left alone. It's hard to tell somebody how to get from Point B to Point A if we don't know what A & B are to begin with. Not obvious what you're starting out with (hacked-up harness? Perfect harness? Auto trans harness? etc.) and what you want to end up with ("clean up the engine bay" aka hack the hell out of everything and then wonder why nothing works right? repair rodent damage and restore to original? auto –> manual trans swap? repair some one thing or other that's not working? etc.)
Likewise, not sure about "not a fan of fusible links". They're far and away the best way of doing what they do, especially for the price. I can't imagine anything that would work as well and last even half as long that wouldn't cost 50 times as much; and I've been an electrical engineer for near 50 years now. Doesn't really seem to be anything wrong with those. Probably best to leave them alone.
The harness you have in your hand in the first pic goes to stuff near the starter. Wires w FLs and big terminals go on the big stud on the starter underneath the batt cable terminal. Fat wire w small ring terminal goes on the "S" terminal of the starter. Note that on some starters, specifically ones that are also compatible with points igntion cars, there's also a terminal "R". Don't put it there. Small wire w plug-in goes to the knock sensor which is in the block right next to the end of the starter motor.
The thing on the orange wires is a splice. Takes the one incoming orange wire and splits it up to multiple destinations. Looks factory to me; there are several of those like that, here and there throughout the car. Not sure what you're asking about there. Probably best to leave it alone.
An automatic car has the B/U light sw on the shifter, in the console. A stick car has it on the side of the transmission. Not sure about your year, butt since GM has used the same wire schemes and colors for all their cars for a given purpose since time immemorial, it's probably the same as it was in the earlier cars, that I have the FSM for. In those the "universal" part of the harness went to the shifter, and in the stick cars only, those wires were extended to C100 to pass out toward the transmission. That extension was not installed in auto cars. It would be eeeeeeezzzzy enough to get acoupla terminals for each side of C100 out of a junk car, any GM car of the era should do fine, and add those wires to any vacant cavities of C100. The wires are dark blue and light green; if you look at your shifter you'll probably see them. You could even be neat and sanitary about it and just put terminals on the end of your extension at the shifter end, so that they would plug into the dark blue and light green wires there.
Not sure about "sort and separate" and "3 relays" and all that; sounds mostly like stuff that needs to be left alone. It's hard to tell somebody how to get from Point B to Point A if we don't know what A & B are to begin with. Not obvious what you're starting out with (hacked-up harness? Perfect harness? Auto trans harness? etc.) and what you want to end up with ("clean up the engine bay" aka hack the hell out of everything and then wonder why nothing works right? repair rodent damage and restore to original? auto –> manual trans swap? repair some one thing or other that's not working? etc.)
Likewise, not sure about "not a fan of fusible links". They're far and away the best way of doing what they do, especially for the price. I can't imagine anything that would work as well and last even half as long that wouldn't cost 50 times as much; and I've been an electrical engineer for near 50 years now. Doesn't really seem to be anything wrong with those. Probably best to leave them alone.
The harness you have in your hand in the first pic goes to stuff near the starter. Wires w FLs and big terminals go on the big stud on the starter underneath the batt cable terminal. Fat wire w small ring terminal goes on the "S" terminal of the starter. Note that on some starters, specifically ones that are also compatible with points igntion cars, there's also a terminal "R". Don't put it there. Small wire w plug-in goes to the knock sensor which is in the block right next to the end of the starter motor.
The thing on the orange wires is a splice. Takes the one incoming orange wire and splits it up to multiple destinations. Looks factory to me; there are several of those like that, here and there throughout the car. Not sure what you're asking about there. Probably best to leave it alone.
An automatic car has the B/U light sw on the shifter, in the console. A stick car has it on the side of the transmission. Not sure about your year, butt since GM has used the same wire schemes and colors for all their cars for a given purpose since time immemorial, it's probably the same as it was in the earlier cars, that I have the FSM for. In those the "universal" part of the harness went to the shifter, and in the stick cars only, those wires were extended to C100 to pass out toward the transmission. That extension was not installed in auto cars. It would be eeeeeeezzzzy enough to get acoupla terminals for each side of C100 out of a junk car, any GM car of the era should do fine, and add those wires to any vacant cavities of C100. The wires are dark blue and light green; if you look at your shifter you'll probably see them. You could even be neat and sanitary about it and just put terminals on the end of your extension at the shifter end, so that they would plug into the dark blue and light green wires there.
That was an awesome response sofakingdom.
I really only need the wires in the c100 to power my gauges, send a signal to my fuel pump, and complete the circuit for my reverse lights. But after you informing me those extensions are only in a 5speed car. I’ve looked for the blue and green wires at the shifter but don’t see those. If I can complete the circuit there no need to add them in the c100. If the usable links are a good idea I can use them. Cheap and purposeful.
it’s a 91 automatic 350 car.
Not sure what I'm looking at in those shifter pics, besides abuncha Scotchlocks aka HACK JOB. I have not the vaguest dimmest foggiest remotest hint of a whiff of a glimpse of a clue what that thing with the yellow connectors and the arrow and the **** is, I don't think I've ever seen anything quite like it. Somehow doesn't look factory to me butt I could be misshapen about that. Butt be assured, the wires you need are in there somewhere; the light turned on SOMEHOW in the car originally, and that's the ONLY place the mechanical motion needed to cause that, is present. If someone was SO LLLLLAAAAAAAAZZZZZZY that they used Scotchlocks for whatever they were doing, thinking they were "good enuff fer gummint work", then they probably didn't bother doing anything else that wasn't absolutely required of them, either. Might have to dig back into the harness a little ways to find em.
Not sure what I'm looking at in those shifter pics, besides abuncha Scotchlocks aka HACK JOB. I have not the vaguest dimmest foggiest remotest hint of a whiff of a glimpse of a clue what that thing with the yellow connectors and the arrow and the **** is, I don't think I've ever seen anything quite like it. Somehow doesn't look factory to me butt I could be misshapen about that. Butt be assured, the wires you need are in there somewhere; the light turned on SOMEHOW in the car originally, and that's the ONLY place the mechanical motion needed to cause that, is present. If someone was SO LLLLLAAAAAAAAZZZZZZY that they used Scotchlocks for whatever they were doing, thinking they were "good enuff fer gummint work", then they probably didn't bother doing anything else that wasn't absolutely required of them, either. Might have to dig back into the harness a little ways to find em.
It might be. I've never seen anything like it, butt there's lots of things in the world that exist in spite of me never having seen anything like them.
If it's original, and/or the only electrical thing that moves along with the shifter, then you could use your digital multimeter to identify which 2 terminals are shorted together when the shifter is in P & N butt no other gears, which would be the neutral safety switch; and which 2 are shorted in R only, which would be the BU lt sw.
That was an awesome response sofakingdom.
I really only need the wires in the c100 to power my gauges, send a signal to my fuel pump, and complete the circuit for my reverse lights. But after you informing me those extensions are only in a 5speed car. I’ve looked for the blue and green wires at the shifter but don’t see those. If I can complete the circuit there no need to add them in the c100. If the usable links are a good idea I can use them. Cheap and purposeful.
it’s a 91 automatic 350 car.
For those of you that are not familiar with newer GM Vehicles (or even the 1991-1992 F-Bodies), All Delphi Electrical Connectors that are produced in Yellow Thermoplastic are for Supplemental Inflatable Restraints.
The Component in the Images above is the Passenger Compartment Collision Impact Sensor for the Supplemental Inflatable Restraints (Air-Bags).
What’s a “good” 12v source from the c100 to connect my reverse light switch? From what I’ve read all I need is 12volts into the reverse tail light switch, then out into the green wire to complete the circuit. 91-92 z28s are def different Than everyone else’s. The service book even says there’s a dark blue but I can’t find it. Thanks vorteciroc
If you don't already have factory wires populated in C100 that you can use, then it might be easier to route your transmission switch wires with the engine harness through the passenger side kick panel and then make a plug that connects into your factory backup wires near the shifter. That's what I would do in your situation.
If you don't already have factory wires populated in C100 that you can use, then it might be easier to route your transmission switch wires with the engine harness through the passenger side kick panel and then make a plug that connects into your factory backup wires near the shifter. That's what I would do in your situation.
that’s pretty funny lol. I’m pretty sure that’s original. 
