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Wiring Harness & Missing Wires


New Member
August 8, 2018
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City, State
Small Town, TX
Year, Model & Trim Level
Hello all! I wanted to see if I could get some guidance on my wiring harness. I picked up a 99-01 Explorer 5.0 engine, PCM and harness recently (huge thanks to Pontisteve on eBay for tuning the PCM!) and I'm trying to piece together the last missing parts I have. As you can probably tell, I've had to patch this harness in a couple of places already so I'm trying to finish it up.

I have a few stray wires circled in red in the pictures below, and I was hoping someone might be able to either spoon feed me what these wires go to or at least point me in the direction of a 99-01 specific wiring diagram. I found the 96-97 one but no luck on 99-01.

I should mention before moving forward that this harness won't be going into an Explorer, I'm using it on the engine/transmission/PCM for a swap project I'm currently working on. So not all wires will be used, and that's okay. I just need to finish piecing together what's needed to run. I was able to trace down a fuse box diagram and find the relevant fuses required for startup. From what I can tell, these are the fuses/relays I'll need:

10A - DLC Connector
7.5A - Brake Pedal Position Switch (Bypass?)
20A - Brake Pedal Position Switch/Pressure Switch (Bypass?)
25A - PCM Power Diode
10A - Electronic Shift Control Module
15A - Electric Shift
50A - Ignition Switch/Starter Relay

I sourced out a 6x6 fuse box online that holds 6 fuses and 6 relays. I plan to purchase the relays needed and throw it altogether with the harness as opposed to using a bulky OEM fuse box found in Explorers. Admittedly, I'm having issues finding the PCM Power Diode so any help in that area would be greatly appreciated!





Explorer Addict
July 30, 2009
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City, State
Florence, KY
Year, Model & Trim Level
1998 XLT 4WD 4.0L SOHC
Can't help with the harness, but if you aren't going to use the original fuse box (which is where the PCM diode is), you don't necessarily need the exact Ford part # diode.... it's just a diode, though you could pull one from a junkyard. I don't know the part # but there are several that would work on ebay... search "Ford Diode". You probably already have an idea what they look like but here is one, but I don't know if it's the same as the original:

You might not even want the original if using a standard blade configuration, fuse box, because the Ford diode has one of the two blades, rotated 90 degrees to prevent someone from accidentally inserting a fuse by mistake. There are other automotive diodes with the two blades, the same as fuse blades so they will fit in a fuse box's normal inline blade orientation:

If you just want something soldered in series on the power lead, maybe something like this:

You're welcome to look through the wiring diagrams linked below in my sig, but I don't know if they are applicable to differences in '99-01 5.0L