Speartech Wiring Harness Rework
 

So I am in the middle of my LS Swap and went with a harness rework from Speartech. Needless to say I am a little disappointed and need some help/guidance. I knew the PCM would not fit in the original factory placement, and I can live with that. However, they said it would be a simple, ready to install harness when it was returned. Well, that is highly incorrect. Has anyone gone with this option before? There are wires that I have to connect to the tach, ac fan, etc that need to go through the firewall (don't even get me started that the wires start on the passenger side of the engine.....). Just not sure what to do next, or if I am just out the $500 they charge for the rework. I am not good with electrical, so I am hesitant to just jump in and modify the wiring under the dash...


Any help or thoughts would be greatly appreciated.

Re: Speartech Wiring Harness Rework
 

You have to tell what they did, or provide some pictures before help can be rendered. They must have labeled stuff or given directions, did you call them and ask?

Re: Speartech Wiring Harness Rework
 

Attachment 294502

Attachment 294503


I have attached 2 pictures. One of the overall diagram, and one of the harness. I have started installing the harness already. Just the top half of the engine (injectories, accessories). I still need to plug in the tranny and the o2 sensors. I tried to flip the PCM to be on the driver side, but then the starter and o2 sensor on passenger side won't reach. Unless I am just completely wrong in the way I am looking at this.


On the harness pic itself, you can see all the wires wound up and labeled to what they go to.

Re: Speartech Wiring Harness Rework
 

If its wired like the diagram its pretty well sorted out. I don't see any sensors in that diagram though.

Should be a VSS and Tach output in there somewhere though.

Thirdgen gauges for coolant temp and oil pressure are separate from the ECM and you run those individually.

Re: Speartech Wiring Harness Rework
 

Which sensors are you not seeing? I do not have wiring for the VSS. I do have wiring for the tach and speedometer though.


So do I need to remove the coolant temp and oil pressure out of the overall harness and run those separately?

Re: Speartech Wiring Harness Rework
 

NM, I opened up the pics so I could see them at full size vs the TGO preview window.

If the sensors are already in the harness they probably have an un-terminated signal wire that you need to wire into the thirdgen harness. Almost all of the sensors route through the C100 block on the driver side.

VSS, and Fuel Pump wiring go through the passenger side though It think. Its been a while.

This is the C100 block on the driver side. You need to match the sensor wires in the harness with the pin out.


https://cimg9.ibsrv.net/gimg/www.thi...d3160c3d9e.gif



C100 Diagram

Re: Speartech Wiring Harness Rework
 

Sorry for all the most likely, stupid, questions. But do I still need the original wiring harness to complete this? I don't have the connector that goes into the C100 block. I am hoping I don't need that still since I don't have the original harness anymore....

Re: Speartech Wiring Harness Rework
 

You'll have to splice some wires inside if you want all the gauges to work. Get a harness form a V6 car from someone for the C100

Re: Speartech Wiring Harness Rework
 

Ya you need the c100 from the third gen. It has the power and starter wires along with the gauges.

Re: Speartech Wiring Harness Rework
 

Don't forget all the front end wiring for headlights, signals, and the windshield fluid pump.

Re: Speartech Wiring Harness Rework
 

So if I get a c100 harness from a v6 I can just splice the wires to the box as opposed to running them all the way to the dash correct?

Again, sorry for all the questions.

Re: Speartech Wiring Harness Rework
 

Essentially, but as Black18Ice stated, it also has the starter wire. you really do NEED the C100.

Have you read the stickies at the top of this forum? That should answer most of your questions

Re: Speartech Wiring Harness Rework
 

C100 is different between years and models. Some stuff doesn't change, but others do. So you'll really need to do some research to get the diagrams for your year/model car.

C100 can be gotten from any thirdgen, but if its not from your year/model you may have some re-pinning to do.

Re: Speartech Wiring Harness Rework
 

I might have a harness for sale real quick here. The bulk head part from the C100. Just waiting for Pocket to reply back to a PM. I'm in need of a fuse block wiring and I want to go his direction.

Re: Speartech Wiring Harness Rework
 

Yup, thats a standard stand alone conversion. Take an OEM harness, cut off the original body connectors, add a fuseblock and pull the necessary connection wires out. Looks like its missing fan/AC relays too

Also, correct you need a C100, but also need a c207 and HVAC connector. Your 91 can use any 90-92 V6, TBI or junky TPI harness to modify. 88-89 harnesses are similar, but some changes need to be made for complete function. I covered what needs to happen to the 3rd gen harness in a previous thread thats linked to the LS1 swap sticky

I am making new C100's in my limited spare time if you dont want to chop up a 25 y/o harness

Re: Speartech Wiring Harness Rework
 

Gonna raise this post from the dead as I finally made some progress on the swap.


I got a TPI harness from someone and started to chop it up based off of Pocket's prep harness prep thread he put out there that is now stickied.


Coming out of the C100 are as follows:
1. 2 long red wires. According to the pinout, 1 is for the Power Dist and 1 is for Power Dist Ign Sw. Does this go for the fuse block I am supposed to add?
2. Tan/White - Brake sense
3. Pink/Black - Emissions Common (removed)
4. Purple - Starter
5. Black/White - I have two of these. One is for ground, the other is for SRS. What is the SRS?
6. White - Tach
7. Tan - Oil Pressure Gauge
8. Purple - Torque Converter Clutch (I removed this one but can add it back if needed)
9. Pink - Ign
10. Dk Grn - Coolant Temp Sensor
11. Grey - Fuel Pump Relay (If I am running a Racetronix fuel pump hotwire kit, do I still need to hook this one up?)
12. Brown - Fan Relay




















I also have the c207 and the HVAC wires not shown.


I am not sure where to go next since in his thread, Pocket just says to connect them, but doesn't give much explanation as to how. I don't like wiring. Have I mentioned that yet?

Re: Speartech Wiring Harness Rework
 

1) Both large red wires need to be connected to battery 12v

2) Brake warning switch -not required but if its got the connector, just snap it on the prop valve

3) I use this to power HO2s and trans IGN points. Since you have an external fuseblock added, use it to power it up. There should be a small pink wire labelled ignition switch

4) Simple

5) Ground both. Supplemental Restraint System aka airbag

6) Simple

7) Simple

8) Its actually connected to the brake switch and is used for TCC. Your stand alone harness should have a ppl wire labelled brake

9) I dont use the large pink on F4, but it can also be used to power up the fuseblock. It is unfused so I dont like connecting it to stuff that can be overloaded like trans solenoids

10) See if the CTS conenctor was exchanged for a 3 wire version. If the old two wire CTS is left, youll have to modify a sender or drill the right cyl head

11) Yes. Racetronix utilizes a plug and play harness so the OEM wiring is retained. The old relay is used to energize their relay, so you still need to send 12v through it for the FP

12) This is the 12v leg of the fan relays. The PCM will ground the other side of the relay to energize the fans. Check what your stand alone has, it may already have a fan fuse wire

HVAC is simple. Red gets battery 12v, BLK grd, LT BLU is AC request. DK grn/wht not used if present

Check the pinout of your year C207. Identify which wires are coming from your stand alone, and ignore the rest. Speedo, MIL, P/neutral definately need to be connected. INJ1/2, ECM can be ignored

Re: Speartech Wiring Harness Rework
 

So on the HVAC, I am not sure where the connector goes? Is it supposed to be cut off?? I uploaded an image below.


Off the connector, I have a red (12v source) where should I splice this to? black (ground), and light blue (this goes to the plug in on the small tube that connects the condenser and evap canister). There is a small green wire coming off from this plug. Where does this connect to? The only open wires I have for the AC is the green one off the Speartech harness, and then the wires coming out of the relay on the C100. Not sure where they all go!

Re: Speartech Wiring Harness Rework
 

Thats for the HVAC. 12ga red is battery 12v, 12ga blk ground, lt blu ac request to the PCM

The other small connector is a pressure switch off the back of the R4 compressor. If you're not using the R4, then toss it

Re: Speartech Wiring Harness Rework
 

I know it is the HVAC, but I don't see anywhere it can actually plug into. The only plugs I have open back there is the blower motor plug, and the blower resistor on top of the big black box.

The light blue wire is going to the pressure switch on the back of the r4, if I am using the R4, do I need to use the Green/white wire to splice into the speartech harness? I have a green/white wire on the speartech harness labeled AC. Not sure if it goes there, or goes to the AC relay somewhere.

Re: Speartech Wiring Harness Rework
 

Well, I figured out why I can't find where I need to plug in the HVAC system. It's not coming out of the firewall like it is supposed to be. Where does it go once in the car? I am trying to see if it got tucked up in there, or if I need to replace the entire harness. Any help is appreciated.

Re: Speartech Wiring Harness Rework
 

Its a small harness that goes from the HVAC headunit to that connector in your hand and has two vacuum lines coming off it

Be aware its 90-92 specific for your car