Lbz swap harness info for fellow members.

clrussell

pro-procrastinator
Sep 23, 2013
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Posting this for another member since he can't get ahold of ben at the moment.



There are some bundled up wires with the harness.

1. The long tail with the 2-pin connector is for the output speed sensor on the transmission/transfer case
2. The two black wires that are in that long speed sensor tail are for the reverse light switch...when these two wires get tied together, the reverse lights will turn on
3. The tail with the ground gray 1-wire connector gets plugged into your oil pressure sensor
4. The long brown wire with the pin crimped onto the end is for the clutch pedal position switch. That wire is going to go to pin position F of the clutch pedal switch connector. The wire that is already in there is GRAY. You can either splice this brown wire into the gray wire ("T" it in), or you can disassemble the connector with a small screwdriver, remove that gray wire pin, and slip the pin from the engine harness in its place....
5. The yellow/orange wire twisted pair goes to the OBD port. Unbolt the OBD port, remove the two blue plastic retainer clips, and then slip the ORANGE wire (GMLAN +) into pin position 6, and the YELLOW wire (GMLAN -) into pin position 14.




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vcr

New member
Sep 22, 2015
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Thanks for your help so far. I am nearly done with the swap. I have just a few questions left for anybody who is more familiar with this than me

1. I have a blue wire with white marker coming out of the harness where the two wires that go to the obd port come out at. I am not sure what this wire is for or where to wire it into.

2. The fuel gauge is showing empty but the tank is very full. Is this right?

3. The oil pressure gauge is way past 80 psi. I am using the lbz pressure sensor. My understanding was that I would have to use the lb7 sensor. The lb7 sensor threads are different so it will not screw into where the lbz sensor is. And if it did the there is not an obvious way to connect it to the harness.

4. The alternator is not charging. Do I need to swap the lb7 alt or can I keep the lbz alternator.
 

RPM Motorsports

smokinum
May 13, 2008
3,271
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38
Central Valley Ca.
1. Possibly the tap shift signal? There are only three wires pulled from the fuse box area into a cab when I do the conversion.., two to the OBD port one to the tap shifter.

2. Tank parameters need to be reversed in the tuning with EFI live and will read correctly.

3. 01/02 sensor is one wire, 03+ are not. If Ben says use earlier sensor, then it needs an 01/02 sensor.

4. Alt will not matter, you have something else going on. It's plugged in, and has the charging cable from the back to the + junction by the power steering box?
 

vcr

New member
Sep 22, 2015
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I have the green and white wire hooked into the obd. In an ealier email Ben has said that the yellow wire was for the dsp5 switch.

I was thanking the same thing as far as the tank parameters. I must be doing something incorrectly. Surely the ecm was programmed before Ben shipped it back.

The oil pressure sensor from the lb7 would not screw into the lbz oil pressure sensor port. It seems that the threads were different.

I am not sure on the alt. Everything is connected properly. I will come back to that.
 

clrussell

pro-procrastinator
Sep 23, 2013
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Do you have a wire loom coming out of the harness ben sent that looks like this?

945f74d1c79c400e165707be37cbca64.jpg



I had to use the factory lb7 oil pressure fitting in the front oil galley plug. Then plugged my harness into it. The wires come out from the harness ben modified.

I had the same charging issue and ended up wiring up a relay that was key hot to send power to make the alternator charge. Neither alternator worked for me and it was a known problem to ben which we never got figured out.


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clrussell

pro-procrastinator
Sep 23, 2013
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On the fuel tank had the same issue. It's in the tune file. Ben had to modify the sensor reading and now it works.

I can look up the sensor scale for you if you have efi and are know how to use it.


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vcr

New member
Sep 22, 2015
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The only wires coming out of the harness that are not connected are the following

1. the yellow wire that I am thinking is for the dps5 switch.

2. The blue wire the white tracer.

Both of these have to no connector on the end


The big connector on the ecm hole 77, is connected to the blue wire with the white tracer

It doesn't appear that the yellow wire is connected is connect anywhere to the big ecm connector
 

vcr

New member
Sep 22, 2015
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Also there is no plug on the harness that will fit the oil pressure sensor from the lb7 motor.

Not sure if this is helpful but I am also getting a reduced engine power notification in the dash as well

One more thing to note, when testing the big connector on the ecm, there is already a wire in of the holes for the dsp5 switch. It is not the yellow that is run into the cab though.

I am so close to finishing this up. Does anyone know how to get ahold of Ben. I feel like he could clear this up for me pretty quickly
 
Last edited:

clrussell

pro-procrastinator
Sep 23, 2013
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Do you have throttle pedal while truck us running ?

I had same message until I put an lbz pedal and wiring assy on it.

I havnt seen ben post in a week or so.. Maybe he is out of town at a wedding?


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vcr

New member
Sep 22, 2015
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I do have an lbz petal. I will try that.

I do but it feels numb. Something seems not right
 

vcr

New member
Sep 22, 2015
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The lbz petal solved the reduced engine power problem.

The petal seems right now
 

clrussell

pro-procrastinator
Sep 23, 2013
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I do have an lbz petal. I will try that.

I do but it feels numb. Something seems not right


It seems like it has dead pedal with the lbz pedal plugged in or the lb7 plugged in?


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vcr

New member
Sep 22, 2015
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After plugging in the lbz petal all is well. The reduced power message has gone. The petal feels normal now. The truck will rev up normally.
 

vcr

New member
Sep 22, 2015
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Now that the reduced engine power message has been solved on to the next question. The blue wire with the white trace. This wire comes out of the bt diesel works harness near the bale connecters. Does this wire need to be connected to 12v. Could this wire send power to the ecm?
 

clrussell

pro-procrastinator
Sep 23, 2013
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Now that the reduced engine power message has been solved on to the next question. The blue wire with the white trace. This wire comes out of the bt diesel works harness near the bale connecters. Does this wire need to be connected to 12v. Could this wire send power to the ecm?


I wouldn't hook that to anything without talking to ben..


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clrussell

pro-procrastinator
Sep 23, 2013
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Just looked on my truck. It has a single brown wire coming out in the same location you describe that goes to my oil pressure sender.

Does you'rs have a plug in on it or just wire with no end?


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vcr

New member
Sep 22, 2015
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Just a wire with no end. This wire originates from the the large ecm connector. Pin hole 77. When I look this up on all data it indicates that this wire is a power wire.
 

clrussell

pro-procrastinator
Sep 23, 2013
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Just a wire with no end. This wire originates from the the large ecm connector. Pin hole 77. When I look this up on all data it indicates that this wire is a power wire.


I guess try hooking it up to power then and see if your alternator charges? Mine does not have a single blue and white wire at that location.


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clrussell

pro-procrastinator
Sep 23, 2013
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What exactly is all datas description of that wire?


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vcr

New member
Sep 22, 2015
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I just received a reply from from Ben. The blue wire with white stripe is supposed to hook up to the lb7 oil pressure sensor. But there is no connector in the end of the wire. I am going to see if I can solder the connector from the lb7 harness onto the blue wire with the white stripe tomorrow morning. We shall see.

Thanks again for all your help