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Who doesn't love a good rabbit hole?

You know me, I get carried away.

@TheGhost Since you have the MT, we can clear up the diagram on EL-86 a little, but I also think we're dealing with a couple small discrepancies. Keep in mind a lot of these diagrams also show items you might not see on your truck. Here's the breakdown of EL-86, with the bold harnesses IDs being what you should expect to see on your truck: 1E = Typo #1. It says "M/T Model", but EL-81 says harness 76M is for "VG30E engine A/T model". EL-44 shows 1E as having 6 wires for AT, and you've indicated there's 8 wires. So, this won't be on your truck. See 5E. 2E = "Back-up lamp switch", found on MT-33 as "Reverse lamp switch" on the OD gear case. EL-30 says it has white/black and red/black wires and confirms as using harness 2E, and that harness 5E has 8 wires. The inhibitor switch on an AT provides the reverse signal, which is likely why 1E is 6-wire. 3E = "Neutral position switch", also on MT-33 by the same name, also on the OD gear case. As such, this is the neutral switch for the transmission. More on this later... 4E = "Transfer switch" aka "4wd switch", per EL-44. This should be your rear-most sensor, or "Transfer Switch #2" in your sketch. In the picture you last uploaded, I believe the harness circled in green needs to be connected to the open harness in your hand given the yellow and black wires indicated on EL-44. (The picture's too small for me to assert much, though.) EL-44 also confirms that 4E is for MT, but does not show an expected 6E harness label by the AT switch. 5E = Typo #2; says "4WD A/T Model", but EL-81 says harness 78M for "VG30E engine M/T model". Everything else has so far confirmed this should be an 8-wire harness on MT trucks. 6E = I suspect this is the correct harness for the AT Transfer Switch, but the diagram is wrong in indicating that it's two harnesses. 7E (AT) & 8E (MT) = These Vehicle Speed Sensors won't be mistaken as switches...they'll have a cylindrical body coming off them. Wires will be red and white Given the various EL diagrams, these appear to be the pins for 5E (note that the numbers from the terminal side, so they might be reversed depending on how you're looking at it): 1 - white/black (2E - Back up light switch) 2 - ? (3E - Neutral Position switch?) 3 - yellow (4E - Transfer/4WD Switch) 4 - red (8E - VSS ) 5 - ? (3E - Neutral Position switch?) 6 - red/black (2E - Back up light switch) 7 - black (4E - Transfer/4wd Switch) 8 - white (8E - VSS) Now, about that neutral switch...or "switches", since I suspect (expect?) both AT and MT models to possibly have both. For sure, there's a neutral position switch on the transmission, either a dedicated switch the MT, or part of the inhibitor switch on the AT. TF-9 shows a switch, and in a different position than MT-33, so I presume it to be a separate switch, but I'm just not seeing proof anywhere...I can't find any circuit diagram that includes it. Normally I'd expect these switches to be covered in the EL - Warning Lamps section because they'd be used to warn of an unsafe condition, such as leaving the t-case in neutral while the transmission was in park (AT) or neutral (AT or MT)...the vehicle can roll. This condition triggers the "ATP" lamp, and while I don't see any mention of it, there is one illustration that suggests it's there. To that extent, I can't find much that covers the MT transmission's NPS circuit, except in the SMJ/"foldout" diagram, though I at least expected to see it as a trigger for deactivating the cruise control, but nothing there. Anywho....more pictures would help, though since 75% of the 5E can be identified, hopefully that's some process of elimination.