Ωhm

True, but more than just page 8 goes through C100. You'd need to go through each page and find all C100 callouts. Didn't in 89 and above they had a connector end view with table of cavity numbers and circuit names. I thought that was what he was looking for.

88 Electrical Manual didn't offer cavity number with circuit ID for its connectors.

Today I found this thing sleeping in a parking lot.

Nice job, good work. Too bad about that box not being level. Any chance of a photo with the box up. Flip your front grill.

No response yet.

Bored, with paint to spare. Nice job.

Is Tach, fuel gauge and temperature gauge your only problems? Does everything else work just fine?

Eliminate Chime Module (CM) as possible cause. Disconnect CM. Does your problem go away? This test could cost you one (1) fuse.

What Year??

What is the file size of your photos?

Block coolant drain plug. Near the ECT sensor.

Double check the vacuum hose to the MAP sensor.

white?? blue?? black?? Looks like soot.

You going to need to look in the harness loom near where the ballast is. Your looking for the Orange wire (fuel pump circuit) to determine if someone bypassed the ballast (two orange wires solder together) or is it a solid wire. Solid wire would mean more work would be required involving the O2 Heater Relay.

Backprobe the TPS (KEY ON: pins B & C) at both Closed Throttle (CT) and Wide Open Throttle (WOT) (note voltage readings) using the gas pedal. Take the same readings with gas pedal disconnected and manually move the throttle between the stops. Compare the voltage readings taken. Should be the same.

Pegged FULL fuel gauge: -Faulty gauge -Open circuit -Check switch on Parking Brake -Faulty brake system -Disconnect connector at parking brakes and see if problem goes away. Check for faulty switch on 4WD unit.

Start with the battery cables, plus and minus, engine block ground, battery plus to starter relay and all the fusible links.

Sounds like good advise here.

I would think the KS is a finely tuned circuit to a specific location.

Is this just a idle problem. Does engine smooth out with higher RPM's?

That's the way to go for the red lens. Replace both lower single filament with a dual filament and wire it just like the MJ. Low intensity bulbs for running/taillights, high intensity bulbs for (L/R) brake/turn/hazard.

Optional choice over the Standard REM.

https://nickintimedesign.com/

Buy a REM (Renix Engine Monitor).

One (1) picture is worth a thousand (1000) keystrokes. OP said he's rewiring. I can't tell where the MJ harness ends and the Ranger harness begins.