Bulkhead connection check

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SmashBack

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Chris
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1979
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Big 10
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6.0
Hey guys, I'm about to do some re-wiring while swapping in a LQ4 engine. Between my color blindness, old faded wires and hard to read black and white wiring schematics I just want to be sure what I'm looking at. The labels I placed on the image are the numbers from the wiring harness schematic.

2J - connected to starter battery terminal
I believe this is the main power source that leads in to the cab?

3 - connected to HEI.
This is just switched power so I will use it to power my main IGN relay on my engine fuse box

6 - connected to starter S terminal
This just powers the starter relay so a 14awg should be ok as a replacement?

25 - connected to alternator
Don't think this will be needed since the PCM harness has it's own wire for this?

2E - connected to junction block on firewall which connects to alt output and starter battery terminal.
Looks like this feeds the IGN switch and a few fuses?

30 - fuel level sender

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chengny

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K3500
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350/5.7
Hey guys, I'm about to do some re-wiring while swapping in a LQ4 engine. Between my color blindness, old faded wires and hard to read black and white wiring schematics I just want to be sure what I'm looking at. The labels I placed on the image are the numbers from the wiring harness schematic.


2J - connected to starter battery terminal
I believe this is the main power source that leads in to the cab?

Yep, it feeds the headlight switch (but only for the H/L's - the other exterior lighting is supplied separately). Also supplies the BATT section of the fuse block (fuses TL/CTSY, HORN/DOME and the two plug-in sockets under the HORN/DM fuse)

3 - connected to HEI.
This is just switched power so I will use it to power my main IGN relay on my engine fuse box

Yes, it would normally be connected to the BATT terminal on the coil.

6 - connected to starter S terminal
This just powers the starter relay so a 14awg should be ok as a replacement?

The wiring dwg shows it as 3mm (equivalent to 12 AWG) but 14 AWG should be okay.

25 - connected to alternator
Don't think this will be needed since the PCM harness has it's own wire for this?

And actually, if you have a gauge package, the BRN 25 is omitted inside the cab.

2E - connected to junction block on firewall which connects to alt output and starter battery terminal.
Looks like this feeds the IGN switch and a few fuses?

Yep, it feeds everything not supplied by the RED 2J circuit (described above).

30 - fuel level sender

Correct - it runs back to the sender within the rear lighting harness loom.

A couple more gauge leads are also shown below (DK GRN 35 & TAN 31) - coolant temp and oil pressure respectively.


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Everything else in that section of the block is pretty much related to the windshield wiper.
 

SmashBack

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Just what I needed, thanks for the assistance!
 

gmachinz

Harnessworx Inc
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Iowa
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Jabin
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Its not a dual tank truck is it?
 

SmashBack

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Big 10
Engine Size
6.0
Nope just one lonely tank under there!
 

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