Hey folks, I posted this here over a year ago, and couldn't find it again, so here it goes again for round 2.
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It really is not too difficult to do. I just recently got done doing it to my car. I had the forward light harness and the motor harness from the 94 Formula when I did it. I also used the factory repair manual for the same year car to look at. I do not know for sure, but I would think that many of the different years had similar harnesses. Here is how to modify your LT1 harness.
Basically, you remove everything that has to do with lights, abs, traction control, cruise control (unless you have the hardware for it...I left mine), horn... It is quite a list.
I also used the fuse box connected to the forward light harness because it had the relay in it for the fan(s). After removing the big seal thingy that goes through the firewall on the driver side, there are two wires that need to have power in run and start. They are (on my 94) a big pink wire, and a big orange wire. I think I removed everything else that went through this connector. I also removed all the heavy guage red wires running to the fuse box which were for components I wouldn't be using.
On the engine harness, there are three different connectors you need to be concerned with. All of these originally went through the firewall and connected to the passenger compartment harness. They are a blue one and white one which both look alike, and a black one which has 4 pins.
On the black, you use two wires. 1) purple is crank. 2) Orange is a power port for the PCM. +12V at all times.
The White and Blue connectors both have 10 pin slots. The orientation of them is laid with flat side on bottom and locking part on top:
K J H G F
A B C D E
White:
A: red wire: Generator feed to inst. cluster. I have it wired w/o an ammeter. It goes wire->300 ohm resistor->positive 12V power in run. DO NOT run w/o the resistor. :
B: tan wire: Oil pressure feed to inst.
C: Brown: Oil level feed to inst.
D: orn/blk: spark retard request
E: Tan/Blk: throttle pos. sensor signal
F: Tan: Serial Data Signal. Needed for using a PCM programming adaptor cable or for attatching your OBD1 connector. Goes to same color spot on OBD1.
G: Dk Grn/wht: Vhicle speed sensor signal.
H: Dk Blu/wht: (Auto) perf. switch sign
(Manual) skip shift ind. sig.
J: Dk Grn/wht: Fuel Pump relay cont.
K: Dk Green: Coolant temp. feed to inst.
Blue:
A: Lt blue: (Auto) perf. switch ind. control
(Man) clutch ant sig (v6 only)
B: Brn/Wht: Service engine soon light. I used a led light for this. +12v -> light -> wire.
C: Wht/Blk: Diag. request signal. Goes to same color spot on OBD1.
D: White: Tach. signal to inst cluster.
E: Dk Blue: Theft det. fuel enable feed.
F: Dk Grn/wht: A/C Request signal.
G: Pink: Power feed from PCM ign Fuse #5. Needs to have pos. power in run and start.
H: Lt. Blue: (Auto) TCC switched power feed
H: Brown: (Manual) power feed from turn P/U fuse #2 to backup switch.
J: Orn/Blk: (Auto) Park/neut. feed from transmission position switch (V8 p. only)
J: Lt Grn: (Manual) Backup lamp feed.
K: Tan/blk: (Auto) torque converter clutch control.
For the wires to the electric fans, there are two different plugs with two wires each. Primary is Light Blue (+) and black (ground). Secondary is Brown (+) and black (ground).
Frankly, I don't know what else to add to this list. If you have questions, respond here or email me.
Jon
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It really is not too difficult to do. I just recently got done doing it to my car. I had the forward light harness and the motor harness from the 94 Formula when I did it. I also used the factory repair manual for the same year car to look at. I do not know for sure, but I would think that many of the different years had similar harnesses. Here is how to modify your LT1 harness.
Basically, you remove everything that has to do with lights, abs, traction control, cruise control (unless you have the hardware for it...I left mine), horn... It is quite a list.
I also used the fuse box connected to the forward light harness because it had the relay in it for the fan(s). After removing the big seal thingy that goes through the firewall on the driver side, there are two wires that need to have power in run and start. They are (on my 94) a big pink wire, and a big orange wire. I think I removed everything else that went through this connector. I also removed all the heavy guage red wires running to the fuse box which were for components I wouldn't be using.
On the engine harness, there are three different connectors you need to be concerned with. All of these originally went through the firewall and connected to the passenger compartment harness. They are a blue one and white one which both look alike, and a black one which has 4 pins.
On the black, you use two wires. 1) purple is crank. 2) Orange is a power port for the PCM. +12V at all times.
The White and Blue connectors both have 10 pin slots. The orientation of them is laid with flat side on bottom and locking part on top:
K J H G F
A B C D E
White:
A: red wire: Generator feed to inst. cluster. I have it wired w/o an ammeter. It goes wire->300 ohm resistor->positive 12V power in run. DO NOT run w/o the resistor. :
B: tan wire: Oil pressure feed to inst.
C: Brown: Oil level feed to inst.
D: orn/blk: spark retard request
E: Tan/Blk: throttle pos. sensor signal
F: Tan: Serial Data Signal. Needed for using a PCM programming adaptor cable or for attatching your OBD1 connector. Goes to same color spot on OBD1.
G: Dk Grn/wht: Vhicle speed sensor signal.
H: Dk Blu/wht: (Auto) perf. switch sign
(Manual) skip shift ind. sig.
J: Dk Grn/wht: Fuel Pump relay cont.
K: Dk Green: Coolant temp. feed to inst.
Blue:
A: Lt blue: (Auto) perf. switch ind. control
(Man) clutch ant sig (v6 only)
B: Brn/Wht: Service engine soon light. I used a led light for this. +12v -> light -> wire.
C: Wht/Blk: Diag. request signal. Goes to same color spot on OBD1.
D: White: Tach. signal to inst cluster.
E: Dk Blue: Theft det. fuel enable feed.
F: Dk Grn/wht: A/C Request signal.
G: Pink: Power feed from PCM ign Fuse #5. Needs to have pos. power in run and start.
H: Lt. Blue: (Auto) TCC switched power feed
H: Brown: (Manual) power feed from turn P/U fuse #2 to backup switch.
J: Orn/Blk: (Auto) Park/neut. feed from transmission position switch (V8 p. only)
J: Lt Grn: (Manual) Backup lamp feed.
K: Tan/blk: (Auto) torque converter clutch control.
For the wires to the electric fans, there are two different plugs with two wires each. Primary is Light Blue (+) and black (ground). Secondary is Brown (+) and black (ground).
Frankly, I don't know what else to add to this list. If you have questions, respond here or email me.
Jon
