LT1 Wiring for dummies
Senior Member
Joined: Sep 1999
Posts: 545
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From: Fairfax, VA
Car: 1987 Trans Am
Engine: LT1
Transmission: T-56
Axle/Gears: 10 Bolt SLP Torsen, 3.73 ratio
Honestly its been a while since I did the stuff, but I'll do what I can.
First off, dont think "its only the wires from xxx I need right?" When I did this, thats how I started out. Instead, just try and find as many things and match them up. Many of the wires go to relays then to fans, fuel pump, etc. The relays have a PCM connection, a fuse, and a ground, so each one has several wires going into it, thats what those wiring diagrams above are. I am still yet to renew my domain, and need to do it soon so those pics may be going down for a bit in the next few days.
If someone happened to have the exact same harness as you have, maybe they can ID it, mine was a 96 ODBII harness, which is partially what made my job so painful, that and not having the relay/fuse box from the doner car. Otherwise, if you have the shop manual, see if you can line things up there, if not, post what the service manual says. If you dont have the manual, most chevy dealers will let you look through a service manual and even photocopy pages for nothing, as long as they arent busy/using the manual/etc. Trust me, it shines a whole new light on the problem and makes wiring that much easier.
Currently my TA is down again with yet another 10 bolt dead (well near death, but thats just a technicality
I have been driving a new GTO since mid december, and have been waiting until I can afford Argon/CO2, Spark Plug wires, moser 9" rear axle assembled, optispark, A/C retrofit, and a baer brake kit to drive the TA again. Currently, I have $0 saved for the project, and wont be able to start saving until may, but then my savings will rapidly increase
First off, dont think "its only the wires from xxx I need right?" When I did this, thats how I started out. Instead, just try and find as many things and match them up. Many of the wires go to relays then to fans, fuel pump, etc. The relays have a PCM connection, a fuse, and a ground, so each one has several wires going into it, thats what those wiring diagrams above are. I am still yet to renew my domain, and need to do it soon so those pics may be going down for a bit in the next few days.
If someone happened to have the exact same harness as you have, maybe they can ID it, mine was a 96 ODBII harness, which is partially what made my job so painful, that and not having the relay/fuse box from the doner car. Otherwise, if you have the shop manual, see if you can line things up there, if not, post what the service manual says. If you dont have the manual, most chevy dealers will let you look through a service manual and even photocopy pages for nothing, as long as they arent busy/using the manual/etc. Trust me, it shines a whole new light on the problem and makes wiring that much easier.
Currently my TA is down again with yet another 10 bolt dead (well near death, but thats just a technicality
I have been driving a new GTO since mid december, and have been waiting until I can afford Argon/CO2, Spark Plug wires, moser 9" rear axle assembled, optispark, A/C retrofit, and a baer brake kit to drive the TA again. Currently, I have $0 saved for the project, and wont be able to start saving until may, but then my savings will rapidly increase 
Junior Member
Joined: Mar 2005
Posts: 1
Likes: 0
From: Watertown New York
Car: '84 Z28
Engine: 305 now, '95 LT1 soon
Transmission: 700R4
Another LT1 swap question(s)
Hi Guys:
I am new to this site and think it is great. Right know I am pulling the 305 (carb) engine out of my '84 Z. I have ordered a complete LT1 engine setup out of a '95 firebird from a local junk yard. They promise me I can have anything I want for $900 except the transmission. I want to run the 700R4 thats in it . As you know, it has a cable speedo. If I understand what I read in this forum, there is a VSS in the dash that will work with the '95 computer? Also, I am sure the bird has a 4L60E which has electronic shifting. Will the new ECM be happy without being hooked up to a transmission? The 305 has headers with a crossover and a dynomax cat back system. Will these shortie headers work? What about the O2's. I want to retain all emissions. And finally, Can you give my a list of stuff I need off the donor car so I don't forget anything. Thank you very much . Bill
I am new to this site and think it is great. Right know I am pulling the 305 (carb) engine out of my '84 Z. I have ordered a complete LT1 engine setup out of a '95 firebird from a local junk yard. They promise me I can have anything I want for $900 except the transmission. I want to run the 700R4 thats in it . As you know, it has a cable speedo. If I understand what I read in this forum, there is a VSS in the dash that will work with the '95 computer? Also, I am sure the bird has a 4L60E which has electronic shifting. Will the new ECM be happy without being hooked up to a transmission? The 305 has headers with a crossover and a dynomax cat back system. Will these shortie headers work? What about the O2's. I want to retain all emissions. And finally, Can you give my a list of stuff I need off the donor car so I don't forget anything. Thank you very much . Bill
Supreme Member
Joined: May 2004
Posts: 2,924
Likes: 1
From: Kingston, Tn
Car: 1987 GTA
Engine: LT1
Transmission: T56
Axle/Gears: 9 bolt 3.70 posi
I have started wiring as well, and it looks like a nightmare to me but I went and got the underhood fuseblock to plug the C100 and get the fan relays for as well, will this make it easier to hook up since I have those now? Or just make it even worse. Also, did any of you use any of the existing ECM wiring or take it out, plus the other set of wiring that come in on the passenger side that plugged into that side of the dash harness?
ok i have read all of the post and i thought that my questions would ne anwsered, but i am lost. I quess the biggest thing is i need the underhood wiring for the 3rd gen. I have a fuel pump relay to run to the 3rd gen pump wire, the ck engine light wire to the 3rd gen. and do i hook up my vats bypass module straight up to my lt1 harness? and also the relays by the brake booster on the 3rd gen are for the fan right? I have new relays that are wired in to the lt1 harness so i dont nee them right. I have directions for the harness from lt130.com who did the harness upgrade but i cant read some of the words. i have most of the wiring done except for the ones that i posted i have no idea were they go to on the third gen harness so if anyone has the 3rd gen harness to post please do or send them to me at ssean72@yahoo.com. Please help i am so close to cranking. thanks sean
Originally posted by xomega
awesome post here. to bad mine is a 96 lt1;p is there much different in wiring on the 96 vs the 95?
awesome post here. to bad mine is a 96 lt1;p is there much different in wiring on the 96 vs the 95?
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Joined: Jun 2006
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hey guys i dont know how to really work this site but i have my 95 lt1 motor running im my 87 iroc the only thing i cant figure out is the alt i have a single red wire coming of the alt and cant figure out where it goes please help send me an email crazywop518@hotmail.com thanks guys
Member
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Joined: May 2005
Posts: 186
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From: Boston, MA
Car: 1988 IROC-Z
Engine: 350 TPI
Transmission: T-56
Axle/Gears: 10-Bolt w/3.08's (dying)
I was wondering if anyone still has some of those pics that are currently marked with the red x? I just got a 94 LT1 from a Caprice cop car.
Member
iTrader: (1)
Joined: May 2005
Posts: 186
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From: Boston, MA
Car: 1988 IROC-Z
Engine: 350 TPI
Transmission: T-56
Axle/Gears: 10-Bolt w/3.08's (dying)
Also, can i use most of this info. for the 94 Caprice LT1? I read some where on here that the wire harness's are different between F and B-bods. The question is, how different?
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Joined: Jan 2007
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95 vs 96
OK i have read this and believe i can do this casue im about to start....I have a 97 ODBI II out of a 97 Z28 and a 96 Crate LT1 with ederbrock proformer heads and cam, 1.6 RR. The question I have is there any or much differance to the diagram posted. I noticed that everything was for a 95 wiring harness. (which i do not have yet and am about to buy to match the ODBI II. can you tell me what needs to go where or can i use the abouve diagram? oh yea its going into a 89 camaro 305 TBI
thanks
thanks
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From: lynchburg va
Car: 1990 chevy camaro rs
Engine: lt1
Transmission: 4l60e
Axle/Gears: 273:(
shbox.com should have everything. i dont think the wiring it to much different. alltho i have noticed a few people have there pcms tuned to a obd1
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Joined: Aug 2007
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Re: LT1 Wiring for dummies
Gentleman; is there anyone that may know it there is the "KISS" keep it simple stupid method. I have this great laminated wiring diagram for my 65 Vette that even a novice could follow. Is there anything like that out there for people like me that have no clue as to what some of these connectors do or go?
I have a 93 Vette motor with all the engine compartment wiring harness in tact. What goes where?
I have a 93 Vette motor with all the engine compartment wiring harness in tact. What goes where?
Supreme Member
Joined: May 2004
Posts: 2,924
Likes: 1
From: Kingston, Tn
Car: 1987 GTA
Engine: LT1
Transmission: T56
Axle/Gears: 9 bolt 3.70 posi
Re: LT1 Wiring for dummies
Most of the motors that were used in the LT1 swaps were either out of F-bodies or G-bodies (more from the F-bodies than G-bodies though) and each car has a different wiring harness. The 'vette and G-body if iirc are one complete harness that goes through the bulkhead connector where the f-body was a seperate harness that plugged into the dash on the passenger side of the car.
Junior Member
Joined: Aug 2007
Posts: 2
Likes: 0
Re: LT1 Wiring for dummies
Thanks so much for your very quick answer but I dont think I asked the question properly. The harness I have is the one you mentioned, a complete engine harness that has a plug into the firewall with a rubber gromet. I need to know what to do with all the wires so I can get it running, I am installing the engine and tranie as a complete unit into a 1947 Chevy Fleetline. I am installing an aftermarket 22 circut wiring harness????????????????
Member
Joined: Mar 2003
Posts: 152
Likes: 0
From: Richland, WA
Car: 1989 Trans Am
Engine: 94 383 LT-1
Transmission: Tremec 3550
Re: LT1 Wiring for dummies
I deleted all mine. Come to think of it though, that should be an independent system from the computer. At least I'm pretty sure they were in my camaro. If they are attached to the stock computer I wouldn't mess with em. Airbags going off cause of grocery carts is no fun.
Junior Member
Joined: Aug 2007
Posts: 18
Likes: 0
From: Chandler, Az.
Car: 87 Camaro RS
Engine: 95 LT1
Transmission: 4L60E
Re: LT1 Wiring for dummies
New member here. I am trying to swap my 87 2.8L to a 95 LT1 out of a buick roadmaster. Will these diagrams work for me? Also what do I have to do to get the 4L60E tranny to connect to my speedo? Thanks for your time!
Junior Member
Joined: Mar 2008
Posts: 2
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From: missouri
Car: 92 RS
Engine: 3.1
Transmission: 700R4
Re: LT1 Wiring for dummies
i am swapping a 97' LT1 w/ computer, wiring and 4L60E, into my currently V6 3.1 92' rs camaro, ive been looking all over this thread and i cant find a post on the v6 wiring, can it still be used for the LT1?? im lost on this whole wiring thing any help would be greatly appreciated
Member
Joined: Mar 2003
Posts: 152
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From: Richland, WA
Car: 1989 Trans Am
Engine: 94 383 LT-1
Transmission: Tremec 3550
Re: LT1 Wiring for dummies
if you go to phot bucket and look at z28*icer's (put an R where the * is)photos he has the wiring for a 92. You may need to do a little hands on research to do a v6 to lt1 swap. I'm putting mine in an 89 bird that was v6 from my 92 camaro. The pinout diagram i got was very close but was al ittle different. I just got out the ohm meter and checked where wires went before I cut them. If you plan on junking the v6 then tracing wires isn't as important.
Member
Joined: Mar 2007
Posts: 185
Likes: 0
From: Slinger WI
Car: 55 chevy Belair & 86IROC Z
Engine: 350 in 55 86IROC Z LT1
Transmission: 55 4speed IROC Z4L60e
Axle/Gears: 12 bolt 410 in55 and 342 inCamaro
Re: LT1 Wiring for dummies
did you ever get you car wired I am doing a 94 vette lt1 into a 86 Iroc and where can you sent pcm for reprograming ?? and are useing a 4l60e trans??
Junior Member
Joined: Mar 2008
Posts: 1
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Re: LT1 Wiring for dummies
Im putting a 94 z LT1 im my old truck I got the motor and trans complete wiring and all, Im not sure how to get the wires that go through the fire wall hooked up so the vehicle will start. Any Ideas!! I am wiring challenged! If anyone has an Idea it would be appreciated
Member
Joined: Mar 2007
Posts: 185
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From: Slinger WI
Car: 55 chevy Belair & 86IROC Z
Engine: 350 in 55 86IROC Z LT1
Transmission: 55 4speed IROC Z4L60e
Axle/Gears: 12 bolt 410 in55 and 342 inCamaro
Re: LT1 Wiring for dummies
I started my wiring today on the C 100 conector the fat pink is spliced to which wire?on 94 lt1 wire harness?? also where does the small pink wire splice to on 94 Lt1 vette harness thanks for your help
Member
Joined: Apr 2008
Posts: 130
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From: Texas
Car: 1991 Z28 1LE
Engine: LB9 305
Transmission: Borg Warner T-5
Axle/Gears: GM 7.5 3.42 Posi
Re: LT1 Wiring for dummies
New member here, longtime motorhead. I have a '93 LT1 from a vette...along with the entire harness and computer. Anyone have a breakdown of this harness? Is it the same as the same year F-body? I am going to put this engine in a '71 Pontiac Ventura along with a muncie 4-speed....manual steering and no a/c.....so I'll be weeding a lot of **** out of this harness.
Supreme Member
Joined: May 2004
Posts: 2,924
Likes: 1
From: Kingston, Tn
Car: 1987 GTA
Engine: LT1
Transmission: T56
Axle/Gears: 9 bolt 3.70 posi
Re: LT1 Wiring for dummies
You would probably be best going to camaroz28.com, alot won't answer questions if it's not related to a thirdgen due to board rules. However PM's are allowed so someone may PM you on this.
Member
Joined: Mar 2007
Posts: 185
Likes: 0
From: Slinger WI
Car: 55 chevy Belair & 86IROC Z
Engine: 350 in 55 86IROC Z LT1
Transmission: 55 4speed IROC Z4L60e
Axle/Gears: 12 bolt 410 in55 and 342 inCamaro
Re: LT1 Wiring for dummies
connector C100 on 86 Iroc ok on the 94 Corvette Lt1 wire harness also has a connector like the C100 where can I get a copy for that as what color of wires is for what thanks
Member
Joined: Mar 2007
Posts: 185
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From: Slinger WI
Car: 55 chevy Belair & 86IROC Z
Engine: 350 in 55 86IROC Z LT1
Transmission: 55 4speed IROC Z4L60e
Axle/Gears: 12 bolt 410 in55 and 342 inCamaro
Re: LT1 Wiring for dummies
is the picture of bulk head connector C100 TERMINAL VIEW AS MOUNTED ON COWL upside down G 1,2, is right side --G 4,5,7,8, is Left side I am working an 86 IROC and the 94 Corvette LT1 wire has a connector like the C100 where can I get information on the wire colors and what there for thanks
Junior Member
Joined: Mar 2008
Posts: 25
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Re: LT1 Wiring for dummies
QUESTION? I'VE STUDIED THE WIRING DIAGRAM ON THE 94 LT1.
ON THE FOUR BULK CONNECTORS ACCORDING TO THE STICKY (POST)DIAGRAM.
THERE'S SOME BLANK WIRES ON SOME AREA ON THE BULK HEAD THAT HAS A WIRE. DO I CUT THE WIRE OUT? AM I USING THE AC WIRING FROM THE PCM OF THE 94 LT1 WIRING HARNESS?
THANKS VIC..
ON THE FOUR BULK CONNECTORS ACCORDING TO THE STICKY (POST)DIAGRAM.
THERE'S SOME BLANK WIRES ON SOME AREA ON THE BULK HEAD THAT HAS A WIRE. DO I CUT THE WIRE OUT? AM I USING THE AC WIRING FROM THE PCM OF THE 94 LT1 WIRING HARNESS?
THANKS VIC..
Member
Joined: Mar 2007
Posts: 185
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From: Slinger WI
Car: 55 chevy Belair & 86IROC Z
Engine: 350 in 55 86IROC Z LT1
Transmission: 55 4speed IROC Z4L60e
Axle/Gears: 12 bolt 410 in55 and 342 inCamaro
Re: LT1 Wiring for dummies
QUESTION? I'VE STUDIED THE WIRING DIAGRAM ON THE 94 LT1.
ON THE FOUR BULK CONNECTORS ACCORDING TO THE STICKY (POST)DIAGRAM.
THERE'S SOME BLANK WIRES ON SOME AREA ON THE BULK HEAD THAT HAS A WIRE. DO I CUT THE WIRE OUT? AM I USING THE AC WIRING FROM THE PCM OF THE 94 LT1 WIRING HARNESS?
THANKS VIC..
ON THE FOUR BULK CONNECTORS ACCORDING TO THE STICKY (POST)DIAGRAM.
THERE'S SOME BLANK WIRES ON SOME AREA ON THE BULK HEAD THAT HAS A WIRE. DO I CUT THE WIRE OUT? AM I USING THE AC WIRING FROM THE PCM OF THE 94 LT1 WIRING HARNESS?
THANKS VIC..
Junior Member
Joined: Mar 2008
Posts: 25
Likes: 0
Re: LT1 Wiring for dummies
HEY GUYS. NEEDS SOME HELP? JUST FINISHED REBUILDING MY ENGINE( 94LT1 ).
OUT OF AN IMPALA SS SO I THOUGHT IT'S WAS A 94, THAT'S WAS WHAT I WAS TOLD WHEN I BOUGHT THE ENGINE. THE ENGINE CAME WITH THE WIRING HARNESS AND PCM. I PRINTED OUT EVERY SINGLE INFORMATION FROM SHBOX.COM. THE PROBLEM IS THE TIMING CHAIN COVER ON THE 94 DOESN'T HAVE A CRANK POSITION SENSOR. ON THE 96-97 ENGINES THEY HAVE ONE.
MY ENGINE HAS ONE. NOW ON MY WIRING HARNESS THE ONLY CONNECTOR THAT FITS THE CRANK SENSOR IS LABELED FOR THE MAF SENSOR..
IF I LEAVE THE CRANK SENSOR DISCONNECTED WILL I HAVE ANY PROBLEMS?
THANKS VIC..
OUT OF AN IMPALA SS SO I THOUGHT IT'S WAS A 94, THAT'S WAS WHAT I WAS TOLD WHEN I BOUGHT THE ENGINE. THE ENGINE CAME WITH THE WIRING HARNESS AND PCM. I PRINTED OUT EVERY SINGLE INFORMATION FROM SHBOX.COM. THE PROBLEM IS THE TIMING CHAIN COVER ON THE 94 DOESN'T HAVE A CRANK POSITION SENSOR. ON THE 96-97 ENGINES THEY HAVE ONE.
MY ENGINE HAS ONE. NOW ON MY WIRING HARNESS THE ONLY CONNECTOR THAT FITS THE CRANK SENSOR IS LABELED FOR THE MAF SENSOR..
IF I LEAVE THE CRANK SENSOR DISCONNECTED WILL I HAVE ANY PROBLEMS?
THANKS VIC..
Junior Member
Joined: Jun 2008
Posts: 42
Likes: 0
Car: 1988 Camaro Conv.
Engine: 96 LT1
Transmission: T56
Axle/Gears: 3:73's
Re: LT1 Wiring for dummies
k i just got out of the garage been working on pulling my motor out all day and finally got it. Now i was wondering if i have to keep the wiring that comes out of the big bulkhead connector to the motor or are they garbage now?
Junior Member
Joined: Oct 2008
Posts: 1
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Re: LT1 Wiring for dummies
Hey guys,I have a 1992 buick roadmaster tbi. I want to install a lt1 from a 1994 roadmaster. Can I be lucky and just plug in the c-100 and delete the vat's to get the lt1 to run? Thanks John
Member
Joined: Apr 2008
Posts: 130
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From: Texas
Car: 1991 Z28 1LE
Engine: LB9 305
Transmission: Borg Warner T-5
Axle/Gears: GM 7.5 3.42 Posi
Junior Member
Joined: Dec 2007
Posts: 11
Likes: 0
From: defuniak springs florida
Car: 1991 camaro rs
Engine: current tbi305 swapping to 94 lt1
Re: LT1 Wiring for dummies
ok i am pretty new at engine swapping my names jacob i have a 91 rs with 305 tbi ....k ive taken the engine out also tranny and the rear end and fuel tank..................and in place i would like to put a 94 lt1 engine and tranny rear end and fuel tank and lines they came off a 94 z28 i have the whole car btw figure that might help but dnt have money
to buy a painless wireng kit i cut most of the wires coming out of my bulk connecter to splice with the lt1 pcm harness ........... but im still not completely sure
im doing it right and would appritiate alittle in put please and thank you ~jacob~
to buy a painless wireng kit i cut most of the wires coming out of my bulk connecter to splice with the lt1 pcm harness ........... but im still not completely sure im doing it right and would appritiate alittle in put please and thank you ~jacob~ 
Joined: May 2004
Posts: 1,037
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From: Kingsport Tenn
Car: 1992 camaro
Engine: LT1
Transmission: 4L60E
Axle/Gears: 3:73
Junior Member
Joined: Dec 2007
Posts: 11
Likes: 0
From: defuniak springs florida
Car: 1991 camaro rs
Engine: current tbi305 swapping to 94 lt1
Re: LT1 Wiring for dummies
Can a moderator please put a STICKY on this and lock it, people are sending me a ton of emails on this and I don't have time to reply to all so I figured this will be a greater help to people:
This will work for the 92-95 LT1s
If you wire the following correctly your car will start on the first attempt.
F-BODY LT1 ENGINE WIRING HARNESS.
VATS 16 pin PASSKEY II
|------------------------|
A8| [] [] [] [] [] [] [] []| A1
B8| [] [] [] [] [] [] [] []| B1
|------------------------|
Slot Wire Color Description
A1 Orn Power feed from ECM BAT fuse #4
A2 Pnk Power feed from ECM IGN fuse #5
A3 DK BLU Fuel enable signal
A4 YEL/BLK Starter enable relay control
A5 GRY "Security" indicator lamp control
B5 BLK/WHT Ground
B7 PPL/WHT Ignition key resistor return
B8 WHT/BLK Ignition key resistor feed
| | Top White 10 pin
|K|J|H|G|F|
|A|B|C|D|E|
K is DK GRN and is the coolant temperature feed to instrument cluster.
J is DK GRN/WHT and is fuel pump replay control
H is empty.
G is DK GRN/WHT and is vehicle speed signal.
F is GRY and is fuel pump motor feed.
A is RED and is Alternator feed to instrument cluster.
B is TAN and is oil pressure feed to instrument cluster.
C is BRN and is oil level feed to instrument cluster.
D is empty.
E is empty or if you have a manuel tranny it is the clutch anticipate signal and is GRY.
| | Top Blue 10 pin
|K|J|H|G|F|
|A|B|C|D|E|
K is TAN/BLK and is (Automatic) torque converter clutch control.
J is ORN/BLK and is (Automatic) park/neutral feed from transmission position switch.
NOTE: If this vehicle is manuel the wire would be LT GRN and would be (manuel) backup lamp feed.
H is LT BLU/BLK and is (Automatic) TCC switched power feed.
NOTE: If this vehicle is manuel the would be be BRN and be (manuel) power from turn B/U fuse # 2 to backup switch and would be brown.
G is PNK and power feed from ECM IGN fuse # 5
F is DK GRN/WHT and is A/C request signal
E is DK BLU and is theft deterrent - fuel enable feed.
D is WHT and is techometer signal to instrument cluster.
C is WHT/BLK and is diagnostic request signal.
B is service engine soon indicator feed.
A is empty.
Black Connector 4 pin
|A|B|C|D|
A is PPL and is ignition (crank starter) (connected to starter relay)
B is BLK/WHT Ground
C is ORN Power feed from ECM BAT fuse #4
D is Empty
C100. It's connected to the underhood fuse block.
|A|B|C|D|E|
|K|J|H|G|F|
| |
A is PNK and is power feed from injector fuse 9
B is DK GRN/WHT and is A/C compressor relay control
C is DK GRN and is A/C compressor clutch solenoid feed
D is TAN and is serial data signal.
E is BRN and is Air Pump Replay Control.(connected to AIR-PUMP solenoid relay)-->(RELAY CONNECTED TO BATTERY)
F is BRN and is power feed from FANS/SOLs Fuse 6
G is PNK and is power feed from ignition fuse 11
H is DK BLU and is secondary coolant fan relay control
J is DK and is primary fan replay control.
K is PNK and is power feed from injector fuse 10.
This will work for the 92-95 LT1s
If you wire the following correctly your car will start on the first attempt.
F-BODY LT1 ENGINE WIRING HARNESS.
VATS 16 pin PASSKEY II
|------------------------|
A8| [] [] [] [] [] [] [] []| A1
B8| [] [] [] [] [] [] [] []| B1
|------------------------|
Slot Wire Color Description
A1 Orn Power feed from ECM BAT fuse #4
A2 Pnk Power feed from ECM IGN fuse #5
A3 DK BLU Fuel enable signal
A4 YEL/BLK Starter enable relay control
A5 GRY "Security" indicator lamp control
B5 BLK/WHT Ground
B7 PPL/WHT Ignition key resistor return
B8 WHT/BLK Ignition key resistor feed
| | Top White 10 pin
|K|J|H|G|F|
|A|B|C|D|E|
K is DK GRN and is the coolant temperature feed to instrument cluster.
J is DK GRN/WHT and is fuel pump replay control
H is empty.
G is DK GRN/WHT and is vehicle speed signal.
F is GRY and is fuel pump motor feed.
A is RED and is Alternator feed to instrument cluster.
B is TAN and is oil pressure feed to instrument cluster.
C is BRN and is oil level feed to instrument cluster.
D is empty.
E is empty or if you have a manuel tranny it is the clutch anticipate signal and is GRY.
| | Top Blue 10 pin
|K|J|H|G|F|
|A|B|C|D|E|
K is TAN/BLK and is (Automatic) torque converter clutch control.
J is ORN/BLK and is (Automatic) park/neutral feed from transmission position switch.
NOTE: If this vehicle is manuel the wire would be LT GRN and would be (manuel) backup lamp feed.
H is LT BLU/BLK and is (Automatic) TCC switched power feed.
NOTE: If this vehicle is manuel the would be be BRN and be (manuel) power from turn B/U fuse # 2 to backup switch and would be brown.
G is PNK and power feed from ECM IGN fuse # 5
F is DK GRN/WHT and is A/C request signal
E is DK BLU and is theft deterrent - fuel enable feed.
D is WHT and is techometer signal to instrument cluster.
C is WHT/BLK and is diagnostic request signal.
B is service engine soon indicator feed.
A is empty.
Black Connector 4 pin
|A|B|C|D|
A is PPL and is ignition (crank starter) (connected to starter relay)
B is BLK/WHT Ground
C is ORN Power feed from ECM BAT fuse #4
D is Empty
C100. It's connected to the underhood fuse block.
|A|B|C|D|E|
|K|J|H|G|F|
| |
A is PNK and is power feed from injector fuse 9
B is DK GRN/WHT and is A/C compressor relay control
C is DK GRN and is A/C compressor clutch solenoid feed
D is TAN and is serial data signal.
E is BRN and is Air Pump Replay Control.(connected to AIR-PUMP solenoid relay)-->(RELAY CONNECTED TO BATTERY)
F is BRN and is power feed from FANS/SOLs Fuse 6
G is PNK and is power feed from ignition fuse 11
H is DK BLU and is secondary coolant fan relay control
J is DK and is primary fan replay control.
K is PNK and is power feed from injector fuse 10.
Junior Member
Joined: May 2008
Posts: 1
Likes: 0
Car: 1996 cavlier
Engine: 96 lt1
Transmission: 4l60e
Axle/Gears: toyota supra irs
Re: LT1 Wiring for dummies
could you help me with my wiring i have a harness out of a 95 caprice police car what wires do i need to hook up to twelve volts const. 12v ign trying to get my cavalier runnig for a show in june any help will be greatly helpfull email me @drastikkreations4u@yahoo thanks
Junior Member
Joined: Jun 2007
Posts: 11
Likes: 0
From: Fresno, Ca.
Car: '88 Camaro
Engine: 5.7L LT1 1995
Transmission: 4L60E (Temporary; Future: T56)
Axle/Gears: Stock Rear -3.23 from 1995 Z28
Re: LT1 Wiring for dummies
Preparing for my LT1 changeover guys -rear end and motor+tranny- all in one shot. My buddies are taking care of the bulk of the install; my task is the wiring and PCM. No problem (hopefully), here's why... Just picked this up from a board member from Santa Barbara...
Having researched the wealth of information on this site concerning wiring an LT swap, the question I have so far is:
By using the C100 connector to wire up the LT with the 3rd Gen (3G), the point of this is to be able to use the fusebox in the 3G without, well...having to replace the fuse box? Is this correct? Everything seems straight forward now that I can view the pictures and make a post... Mr. Admin (JT) for fixing my problem.
Having researched the wealth of information on this site concerning wiring an LT swap, the question I have so far is:
By using the C100 connector to wire up the LT with the 3rd Gen (3G), the point of this is to be able to use the fusebox in the 3G without, well...having to replace the fuse box? Is this correct? Everything seems straight forward now that I can view the pictures and make a post...
Mr. Admin (JT) for fixing my problem. 
Junior Member
Joined: Jun 2009
Posts: 3
Likes: 0
Re: LT1 Wiring for dummies
All of this wiring info is great. What I am planning to do is put a LT! out of a 1994 Caprice Classic SS into a Jet Boat. Most "Boat people" change these engines back to a carburater but I thought that the multi port EFI would add more power. I knpw that GM has a computer that they sell with their crate engines that also comes with a wiring harness. Would any one know what would be the bare minimum wires that could be stripped out of the factory harness to make this engine run properly? Would I be better off buying the crate engine computer and wiring harness and just starting clean? Any help on this would be a big help.
Thanks
P.S. I don't know if I posted this in the right place so if not maybe someone can paste it to the right message board.
Thanks
P.S. I don't know if I posted this in the right place so if not maybe someone can paste it to the right message board.
Joined: Sep 2004
Posts: 5,906
Likes: 240
From: Chicagoland Suburbs
Car: 1989 Trans Am GTA
Engine: LT1, AFR 195cc, 231/239 LE cam.
Transmission: M28 T56
Axle/Gears: 3.23 10bolt waiting to explode.
Re: LT1 Wiring for dummies
You can either convert the stock harness (you'll throw away at least half of it in a boat) or you can buy a Painless harness.
Just specify what year and vehicle your harness/pcm came out of.
Just specify what year and vehicle your harness/pcm came out of.