Let me start by saying if you have any questions about wiring specifics, please leave a comment below! I'll do my best to answer question.

In this episode I start on the engine wiring of of my Ford Explorer 5.0 EFI swap. My plan is to strip down and cut up the stock Explorer harness and integrate it into the Mustang's original wiring. I'm starting by eliminating unused wires and simplifying the harness to run standalone.

Here are my notes I took during the wiring work, hopefully these can help if you're doing your own Explorer 5.0 swap. These will provide you with the PCM pinouts, wire colors, wiring diagram numbers, and my own notes for each of the wires going to the PCM connector. These are for a 1996 model year Explorer, there are some slight differences between 96-01 harnesses. I noted any differences where I found them.

PCM 1 : coil power. Goes to ignition relay. Color: Red/green. Diagram # 16
PCM 2 : Tach signal. Color: Brown yellow. Diagram # 11
PCM 3 : OBD2 port. Twisted with #11. Color: Pink/blue. Diagram # 915
PCM 4 : Brake light switch 12v when pressing brakes. Diagram # 511
PCM 5 : Fuel pump monitor. Color: Green/yellow. Diagram # 238
PCM 6 : Check engine light. Grounds when check engine status (put 12v on other side of bulb). Color: Pink/green. Diagram # 658
PCM 7 : VSS positive outpu. Use for electronic speedo, or cruise control. Color: Gray/black. Diagram # 679
PCM 8 : Ecu memory. Keep 12v hot at all times (battery) fuse 10A. Color: Yellow. Diagram # 37
PCM 9 : Main ecu power. Runs through relay to power on with key on. Color: Red. Diagram # 361
PCM 10 : Empty. Diagram # *29
PCM 11 : See wire 3. Diagram # 914
PCM 12 : Overdrive switch Wire as a ground on momentary switch. Other side of switch gets 12v ign. Color: Tan/white. Diagram # 224
PCM 13 : Missing on later model harness. Color: Pink/orange. Diagram # 676
PCM 14 : Evap. REMOVE. Color: Purple/white. Diagram # 91
PCM 15 : Fuel pump control. Grounds fuel pump to turn on. Color: LT blue/orange. Diagram # 926
PCM 16 : Coolant temp for gauge. Color: Red/white. Diagram # 39
PCM 17 : Fuel tank pressure. REMOVE. Color: Pink/red. Diagram # 791
PCM 18 : Fuel tank pressure. REMOVE. Color: Gray/red. Diagram # 359
PCM 19 : Fuel tank pressure. REMOVE. Color: Brown/white. Diagram # 351
PCM 20 : transmission range (TR) sensor input. Missing on later model harness. Color: Blue/yellow. Diagram # 199
PCM 21 : Reverse light switch. Feeds power to reverse lights. Color: Black/pink. Diagram # 140
PCM 22 : OBD2 port. Used for reflashing. Color: Purple. Diagram # 107
PCM 23 : Empty
PCM 24 : Trans neutral. Wire to +12v on CRANK only. Color: Pink. Diagram # 329
PCM 25 : Reverse switch power. Power INTO the reverse switch. Wire to 12v ignition, 10A fused. Diagram # 298
PCM 26 : Oil pressure for gauge. Color: Green/white. Diagram # 253
PCM 27 : fuel flow rate output REMOVE. Color: Blue/pink. Diagram # 305
PCM 28 : air suspension acceleration input. Missing. Color: Orange/b. Diagram # 394
PCM 29 : Empty. Diagram # 784
PCM 30 : AC compressor control. Remove. Color: Pink/yellow. Diagram # 331
PCM 31 : Neutral safety switch out Plug into "S" terminal on starter relay. Prevents starting while not in park or neutral. Color: Red/blue. Diagram # 32
PCM 32 : Empty
PCM 33 : neutral safety switch in to general electrical module (GEM). Missing. Color: Red/white. Diagram # 463
PCM 34 : Ecu ground. Color: Black/white. Diagram # 570
PCM 35 : Empty
PCM 36 : O2 sensor heater. Power up with o2 sensor relay. Color: LT Blue/orange. Diagram # 34
PCM 37 : A/C kick?. This wire is purple on later models. ??? Feed 12v into it when AC compressor turns on ???. Color: Green/orange. Diagram # 198
PCM 38 : Empty
PCM 39: Purge valve. REMOVE. Color: Green/black. Diagram # 191
PCM 40 : Overdrive off light. Ecu grounds this when overdrive is off. Color: White/green. Diagram # 911
PCM 41 : Empty
PCM 42 : Ecu ground. Color: Black/white. Diagram # 570