Long time listener, first time caller here with my project LeSabre

So I bought this 95 limited LeSabre sight unseen from Georgia a few years ago with 66k on the odometer for $275. Rode down and got the car, then drove it back to Ohio with no problems except stopping in Tennessee for some cheap new tires (old ones dry rotted).



It came with the funky obd1.5 and the L27 3800. While reliable it was entirely too slow for my liking. I feel in love with how well the car drove and rode. So shortly after I got it I ran into a 95 park ave ultra at the junkyard. Went ahead and stripped the lower manifold with injectors/supercharger/throttle body off it along with the engine harness and eprom. Built my own fender well intake, and threw a pulley from a 91-93 m62 on it. Ran a lot better and had some sweet whine from the supercharger but after 15k of beating on it, the stock 4t60 couldn’t take it anymore. So it was time to series II swap it. Also forgot I added some 18s from a Lucerne to snazz it up some.





A couple months after the last pic someone figured they needed it more than me and decided to steal it. I scoured the streets looking for it but always came up empty. Finally three months later the local constabulary called to inform me they found my car and in order to retrieve it I had to pay multiple parking tickets, impound and towing fees (even though it was reported stolen). I ended up paying more there than I did to begin with for the car. The poor thing was destroyed, dash blown into pieces so they could steal my radio (which had the digital climate controller attached still) and finished off the transmission for me.

But in the meantime I found a 03 SSEi for super cheap, bought it knowing the underneath was rotted to crap but really only wanted to drive it a short time and swap the drivetrain to my LeSabre.



Subframe mounting points rusted away from the subframe itself. Otherwise a really nice car that I still have to pick parts off of. I’d like to eventually interior swap my LeSabre with the SSEi stuff but need to get it running first lol. A few month ago I started pulling the drivetrain on the bonne so I could get this party moving. All and all went pretty smooth. Had to modify a series I and II engine mount for the passenger side to work. Used the inner part of the bonne cv axle in order to get my axles right.



And the LeSabre limping around acting as my truck for the day



Now where I currently am. Both cars in their sad current condition. Having a hell of a time getting my wiring harness sorted out. Took me some time to trace wires on AllData so I could figure out which ones I’d have to extend into the engine bay. I grabbed a harness from a 98 LeSabre in hopes of it making my life a little easier, it hasn’t yet lol.







My problem is, the trans from the bonne has a internal nss while the car is provisioned for an external one. That along with not being sure what all I need to adapt into the new pcm to get it to talk with my gauges inside and the fuel pump too. Hopefully someone in here can get me motivated to get this car done already. Also of course I have a baby on the way too so that isn’t helping. So any other swap guys have some tips or better pin outs maybe? Or solutions to using such a newer trans in my older car? Any help is greatly appreciated and hopefully I posted in the correct area.

What you really need to sort out the wiring is the diagrams from the CSM for both cars. The main thing on the NSS is that it locks out the starter in gear, and turns on the rev. lights. The rest of it's functionality (gear indicator) isn't needed on the LeSabre. You could probably grab the external range switch and use that, I've never worked with a '03+ trans so not sure what all of the intricacies of that swap will be.

You've torn into the harness a lot further than I've ever had to. The ouputs for all the gauges are the same, just have to connect the wires. I'll have to go back an look at my notes for the '93 SSEi, but what I did was make an adapter harness to connect the engine harness to the firewall harness. Then I gutted an old PCM, and used the connector and box to act as a relay center and jumper the wires needed to sent the signals to the gauges. On your LeSabre, all the sensors input to the PCM under the dash. On the SSEi, the PCM is in the engine bay. The PCM outputs signals to the cluster for each independent gauge. The LeSabre firewall connector has several wires that only connect the firewall connector to the PCM. There are enough of these wires to re-purpose them using the old PCM shell as a junction to house the jumpers (sending the signal to the right pin on the dash) and add relays and such.

The other option is to grab a complete body harness from a 98 LeSabre (must have the 4t65 trans), which will make the engine harness almost plug and play. But you might have to re-pin the gauge cluster and some other things, I'm not 100% sure what all changed with the '96 facelift. But I do know that the fuel gauge will not read correctly. The LeSabre is a mixed bag, anything that has the 4t60 from the factory uses a 0-50 ohm level sensor, wired directly to the cluster. The 4t65 cars use the newer 50-260 or something like that, the signal goes to the PCM, which outputs the level to the gauge (I think). I have a '97 LeSabre L67 swap car, and I'm still working out issues with my fuel gauge...

Without knowing your level of mechanical skill, or if you can read DC circuit schematics, it's hard to convey every little detail to make the swap work. I'll grab some pictures of my crap, the link to the '93 build (first 10 pages are relevant) is in my signature but I think most of the photos are dead because PB blew it all up and I haven't had time to switch everything over to Imgur yet.

_________________
Boost addict


The Fleet:
'93 SSEi - Twincharged + manual Build thread
'97 Camaro - Top swap
'05 STS - V8, AWD, her DD
'92 Trofeo - Fair weather DD
'99 Montana - top swap 3800
'04 Sierra 2500HD - LLY Duramax

Current project:
Something cool, trust me.

Upcoming projects:
'92 Bonneville SSE
'87 LeSabre T-type
'67 LeSabre

Gone to greener pastures:
'84 Sierra Classic - Twin turbo 3800
'97 LeSabre - Top swap

RIP:
'86 LeSabre - pictures
'93 SE - L67

Thanks for responding, was kind of hoping you’d see this since I know you’ve done plenty of L67 swap. I tore the dash that far apart because I was planning on pulling the body harness and swapping that out. But the donor car got crushed before I could make it back to the yard. But it also has a broken blend door in the center section that I need to source. As far as gutting the pcm, I never thought of that. I was going to repin the 98 engine harness to work with the interior harness that is already there but perhaps that’s the better move. I’ve got pretty much all of the pins figured out for the car side which was a huge pain. I had to track each circuit number to where it ended up. Unlike obd2 that was everything laid out nicer in diagrams.

I have the SSEi harness still to take the extra circuits that are necessary for the extra trans stuff. Was planning on adding those to the 98 harness connectors. Does that seem logical to you? Add a fuse or two like what’s in the factory 03 harness? I’m going to take some time to look through your 93 thread tonight. As far as the nss goes, if I add the circuits to my harness and to the pcm but also throw the external factory one on top of it then I shouldn’t have to chase or rewire car stuff?

I think I'm not quite following.
You have these:
Body harness: '95 LeSabre - or 98 Lesabre ?
Engine harness: '03 SSEi
PCM: '03 SSEi

I'm not up to speed on the '00+ exact differences, but I think you can make what you have work, with a engine harness adapter of some sort because the pinout/key of the '03 engine harness is probably different and I think the '03 cluster is data bus controlled not analogue. I think you have to add wires for each of the cluster inputs, and the adapter you use will need to re-route the NSS connector on the body harness to the PCM harness - the '99 and older cars the NSS connector was not on the engine harness at all. It was part of the drivers side body harness in the engine compartment. You will probably have to connect the wires from the NSS connector to a new 'harness' that crosses to the passenger side where the engine harness adapter is. Check the picture below, you can see how I have a dozen or so wires coming from between the two connectors on that adapter harness. Those wires ended up running to the other side of the engine bay for the cruise control and a few other things you probably won't need to worry about, just illustrating how you can make this adapter harness fit your need.

Giving stuff names - C101 is the connector on the engine harness. Note that this is from the 97-99 H-body, the '03 harness is similar but I don't think it will directly connect to the C101. C101 contains both halves of the connector, one half is on the Body harness, the other half on the engine harness. C265 is the name of the same connector on the '95 harness. The body harness side of C265 does not fit the engine harness side of C101, they are completely different. On the '93 harness, there is a pass-though at the firewall and the connector is actually inside the dash right by the PCM. On he '96+ the connector is integrated with the pass-through.

I dug through the bowels of PB to find this picture of how I made the adapter harness. Again, if you use the 97-99 body harness you won't need the PCM shell, just the adapter to go between the 03 engine harness and the C101 body side connector. Anything that needs to be added to complete the engine harness can be added here, I wouldn't add them to the 98 body harness. In this picture I had to add ~12 wires. Keeping modifications contained to the adapter will help later if you need to troubleshoot:


Here's the full list of circuits on the C101 on the body harness, that need to be connected to the engine harness, to make the car run and all equipment functional. PCM pins are for reference from the '98 L67 H-body OS,.

+12v Run/Start (switched ignition power supply to the engine harness)
C101-D2 Boost Control Solenoid
C101-H7 Fuel injectors
C101-D1 ICM
C101-B5 EVAP purge & HO2 sensor
C101-A2 MAS & PCM C1-19
C101-A3 Transmission

+12v Batt supply from body harness
C101-G7 connects to PCM C1-20

Ground on body harness
C101-L2 to PCM C1-16
C101-C2 NSS
C101-B1 HO2 sensor

PCM Controls - PCM applies GND to these circuits to complete the circuit.
C101-A6 ---> PCM C2-2 (Evap vent control)
C101-B4 ---> PCM C2-35 (fuel tank pressure sensor pin A)
C101-D4 ---> PCM C1-30 (brake switch for TCC control)
C101-D5 ---> PCM C2-39 (A/C Relay Control)
C101-E7 ---> PCM C2-22 (A/C Request)
C101-H1 ---> PCM C1-6 (Low speed fan relay control)
C101-J4 ---> PCM C1-5 (High speed fan relay control)
C101-K1 ---> PCM C2-5 (MIL/check engine light)
C101-K4 ---> PCM C2-6 (Low Oil Light)
C101-K7 ---> PCM C1-75 (Temperature warning light)

PCM outputs - signal/controls (+Vout)
C101-A7 <--- PCM C2-9 (Traction Control delivered torque)
C101-B6 <--- PCM C1-55 (VSS output)
C101-C2 <--- PCM C1-15 (UART to ALDL connector pin 9)
C101-C3 <--- PCM C1-67 (oil life reset switch)
C101-C5 <--- PCM C2-69 (fuel level input from sensor in tank)
C101-C7 <--- PCM C1-2 (CCR output to CCR module pin C3)
C101-D3 <--- PCM C1-59 (Class 2 data to ALDL connector pin 2)
C101-D7 <--- PCM C1-3 (Fuel level output to cluster)
C101-H3 <--- PCM C2-59 (Cruise status to cruise module pin J)
C101-H4 <--- PCM C1-71 (Traction control desired torque)
C101-H5 <--- PCM C2-52 (Performance shift select switch)
C101-J3 <--- PCM C2-33 (+5v ref B out, fuel tank pressure sensor pin C)
C101-J5 <--- PCM C2-3 (+12v fuel pump relay enable)
C101-K3 <--- PCM C1-72 (Cruise control disable, module pin H)
C101-K6 <--- PCM C2-55 (fuel tank pressure signal, sensor pin B)
C101-L5 <--- PCM C2-36 (Oil life indicator to cluster)
C101-A5 <--- PCM C1-39 (fuel pump PWM - SSEi Only)


Other circuits
C101-A4 Oil Pressure Sender - direct to cluster
C101-B3 Coolant temperature sender - direct to cluster
C101-J7 Tach signal from ICM - direct to cluster
C101-F7 +12V signal from ignition to starter solenoid

_________________
Boost addict


The Fleet:
'93 SSEi - Twincharged + manual Build thread
'97 Camaro - Top swap
'05 STS - V8, AWD, her DD
'92 Trofeo - Fair weather DD
'99 Montana - top swap 3800
'04 Sierra 2500HD - LLY Duramax

Current project:
Something cool, trust me.

Upcoming projects:
'92 Bonneville SSE
'87 LeSabre T-type
'67 LeSabre

Gone to greener pastures:
'84 Sierra Classic - Twin turbo 3800
'97 LeSabre - Top swap

RIP:
'86 LeSabre - pictures
'93 SE - L67

Ok to clear that up I have

Body harness is still factory. 98 donor got crushed before I could make it back for the body harness
Engine harnesses - 95 Park Ave Ultra
98 LeSabre (thought it would make my life easier like monte carlo swap guys since its series II already)
03 SSEi (along with fuse boxes too)
PCM - 03 SSEi (I have HPTuners to sort that as well)

Super helpful info from you though as always which I greatly appreciate. I can gut my factory pcm thats inside and do like you did I believe. Just use the SSEi harness and add the jumper to the lesabre body harness. This is what I've come up with as far as wires in my c260 connector at the firewall. Granted I wont have to use most of those but I was trying to locate everything that passed thru so I knew what was what

Excuse my messy handwriting lol



So hopefully I can get a harness going and get some movement on this thing here soon. Ive been driving my back up exploder sport and man is it ever a piece of crap

It's not much worse than my notes for the SSEi are:








The thing that I found annoying though is when there are omissions or errors/conflicting information in the wiring diagrams. In my '98 CSM, there are two distinctly different diagrams for the same connector on the NSS, depending what section you're reading. I don't have diagrams for the '95, only '93, '97, '98 and some from other platforms. I know there are a few others on the forum that might, if they are still around.

_________________
Boost addict


The Fleet:
'93 SSEi - Twincharged + manual Build thread
'97 Camaro - Top swap
'05 STS - V8, AWD, her DD
'92 Trofeo - Fair weather DD
'99 Montana - top swap 3800
'04 Sierra 2500HD - LLY Duramax

Current project:
Something cool, trust me.

Upcoming projects:
'92 Bonneville SSE
'87 LeSabre T-type
'67 LeSabre

Gone to greener pastures:
'84 Sierra Classic - Twin turbo 3800
'97 LeSabre - Top swap

RIP:
'86 LeSabre - pictures
'93 SE - L67

Ive been on the hunt for a 97-99 body harness near me but havent been having much luck. Its been hectic over this passed holiday and the weather has been crap anyway. Hoping to score something this weekend from pull a part. They have a couple 98 Limiteds to pick from so fingers crossed lol