The car is my '86 Iroc with a 305 tpi / 700r4. The original harness was trashed by the P.O., so I bought a new harness from an '87 TPI 305 car. Everything is just about complete with the exception of the distributor and the following connections that I can't figure out.

**NOTE** If you could please respond with a pic of where it plugs in and a description of what it goes to, that would be greatly helpful. Thanks!

The first plug comes out of the wiring harness on the battery side, as shown in pic...


The second pic (If I have the wire in the right place) has a gound that I believe goes in the passenger fenderwell and the wire runs towards the battery (missing plug).


The 3rd plug runs in the wireloom with the ac plug and the temp sensor on the drivers side head.


The last plug comes out of the wiring harness at the back of the motor near the washer pump.


Thanks so much for any help as I am by no means an expert at wiring. I'm probably lucky I got it this far as I replaced the entire harness, computer and distributor.

 

the first one goes into the side of the alternator
im not sure about the second picture.
the third one goes to the pressure switch on the back of the A/C compressor.
i don't know about the last one.

 

Last one iat or egr solenoid ?

 

There is a seperate short harness that connects to the IAT sensor under the plenum

 

last one im thinking is the reverse lights as there is a plug on the tranny that looks like that one and its on the back of the motor where it could go down.

 

the last picture is the intake air temp....it is hidden on the bottom of the upper plenum...there is a pigtail that you seem to be missing

the one with all the tape on it near the strut mount could be for your hood light cant tall though

 

If the two wires are black and tan then its the IAT. If it is black and pink it is EGR.

The first is for a new style alt that is used on a serp system. If you have an 86 you have v-belts. Need to adapt the harness to plug into your alt

Not sure of the second, need a better pic.

The third is the high or low pressure sensor for a/c (black and blue it is high, black and green it is low. 99% sure its that way and not opposite)

 

Sorry, I feel like a retard...
Ok. the two wires are black and pink w/black stripe, so it's egr? Do you have a pic of where it plugs in. I'm having a hard time physically finding where it goes.
Good call on the alternator, mine is the older style after comparing my old harness to this one...so my old harness is a two wire, one red and one brown and the new plug is 3 wire, one red and two brown. Do I run the two brown together as one wire or just not use one of them?
Do you also have a pic of where the a/c sensor goes...again just having a hard time physically seeing it. Thanks so much for everyone's help. Hoping to try and get this thing running again this w/e.

 

There will be an egr solenoid bolted to the back two intake bolts on the passanger side. That is where it goes.
The red will go in the same spot as that is what energizes the alt. The brown on an 86 goes to the volt gauge. On the 87 one goes to the gauge and the other goes to the coolant fan relay. You need to see which one to use.
I dont have a pic. But the high pressure sensor is on the aluminum line that runs on the passanger frame rail to the condensor infront of the rad. If I would have to place the sensor, it is around the strut tower area down by the frame. The low pressure is on the (cant think of the exact name of it, the large cylinder looking thing near the heater box ont he firewall). If you can get a better pic or description of the cut wire I can help out as to what it is/where it goes.

 

Ok, it appears that I already have the EGR and IAT hooked up. The wiring color is a black wire w/pink stripe for the EGR. The IAT is brown and black. So if that's right, then I still have this one plug that IDK where it goes. It wouldn't reach the EGR if I wanted it too. It comes out of the harness on the drivers side. The wire is more like a peachy (or lt. pink maybe) color with a black stripe. The small harness on the passenger fenderwell has 2 wires. One is a ground and the other is a black wire with a red stripe.

First two pics are of the same plug. Just trying to let you see the colors. Second pic is of the small harness on the passenger fenderwell. Thanks again for all your help. Completely rewiring one of these can be a little confusing, especially with changes from year to year.

 

Ok, also checked on the low/high pressure hook ups and they are also already hooked up. The plug in the3rd pic (original post) is on the driverside. It's in the same harness as the temp sensor wire and the a/c compressor plug. It has 2 wires, one Blue w/black stripe and green w/white stripe. So, I still need to figure that one out too.

 

If it is on the drivers side I am just trying to remember what it could be. I will get back to you on that one.

That last one is the electric fan. If you follow that black/red wire, it should go to the fan relay.

 

I still need help with pics 2 - 3 - and 4 if anyone can help. I've given the wire colors above if that helps you help me. Thanks, Jamie

 

I would dump the SI alternator from the 86 and upgrade to the CS144 alternator and keep the same harness connector.

https://www.thirdgen.org/forums/elec...ed-up-alt.html

On the 3rd picture on your original post: is the harness from an AT or MT car? Some of those manual cars have an extra connector for a power steering switch at low speeds.

Take a picture of your a/c compressor so we can see what is plugged in.

I have an 87 TPI 305 car in my driveway, I'll go look at it tomorrow and see if I can help.

 

good info on the alternator. I have a complete 305 tpi engine sitting here with the newer style alternator on it that I could swap. So all I would have to do is swap the pulley and everything else is good? I'm not sure if the harness is MT or AT. I bought it from a member here and don't remember to be honest. The ac compressor the p.o. bought for the car, but it's off a tbi car, so I'm not even positive that it will work right. Any further help will be great. See if you can figure out where that plug goes that's coming out of the back of the harness by the driverside head. Thanks

 

Compressor Clutch Connector (square connector that goes on front of compressor:


Compressor Pressure Switch (round connector that goes on the back of the compressor


Pressure Switch Plugged in:


As for the alternator, I wouldnt use the CS130 alternator, its really small. I would get the CS144 140 amp off of like a 1996 Caprice and reuse the 1986 upper TPI alternator bracket, thats the one to use for this swap. It fits perfectly and no other changes are really needed, except for the belt.

 

Thank you lucid for the great info and pics. It makes it so much easier to figure these things out. So I've got the alternator wiring and ac wiring figured out. Any idea where the plug goes in the 4th pic from the original post? It comes out of the harness right near the oil pressure sensor. There's also the wires in the 2nd pic. I don't even know if I have it in the right place. Just seemed to fit there especially since it has a ground and matched right up to where there was a bolt for a ground.

 

Go to Autozone.com and click on the tab that says Repair Info up at the top.
Register for free where it says FREE Vehicle Repair Guides and log in. Select category, Vehicle Repair Guides (left side) > Chassis Electrical (middle) > Wiring Diagrams (left side)