Removing Engine/Electrical components - Modify Engine Harness? | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Removing Engine/Electrical components - Modify Engine Harness?


February 10, 2005
Reaction score
City, State
Rochester Hills, Michigan
Year, Model & Trim Level
2000 Mountaineer
Well I have a couple electrical/wiring questions... the only thing on the Mountaineer I haven't touched yet.

Here's the back story... I have been building up my 2000 Mountaineer for years now, EE Supercharged rebuilt 306 at about 10lbs, methanol injection, etc. I have been having intermittent issues and over the past winter lost the gasket for the water pump. So now im tearing it down, converting to 2wd and getting everything ready for a motor swap into a 2wd prerunner ranger this fall. I want to get everything running perfect in the mountaineer before the swap. Over the time of the build, I have removed several components from the engine compartment (cruise control, AC compressor and all components, windshield washer tank and a couple other parts). All of which plug into the engine harness... and in the meantime I have just left these plugs hanging, not plugged into anything or even covered. I fear this has reeked havoc on my wiring harness. I am going to be purchasing another harness for the ranger or in case i butcher this one.

My questions being.... when electrical components are removed... does it interrupt a constant circuit that might affect other things plugged into the harness? Is leaving them unplugged ok for the ECU - obviously will need to be covered? Is there any harm in taking apart the harness and removing the wiring for unused components all the way back to the plug on the ecu? <-- this will help clean up the engine bay considerably and maybe someone has done this and done a lil write up :)

Is there anyone on here who has or can link me to a detailed engine wiring diagram for the 2000 Mountaineer/Explorer with the 5.0L?

It sounds like you have been running the vehicle without any ill effects of everything disconnected (although I'm sure the GEM is wigging out) but as far as the harness goes, it will not damaged anything by deconstructing the harness and removing all the affected circuits that are no longer in use. But you have two separate harnesses under the hood - the engine harness itself, which is what the PCM plugs into, and the engine bay harness (it starts at the three square plugs on the driver firewall, has a bulkhead connector to the engine harness, and terminates eventually to the fan/blower motor on the passenger side - in other words, it makes a giant U from driver firewall, to the driver headlight to the passenger headlight to the passengerside firewall)

In the three instances you described, the A/C compressor circuits go from the compressor, through the bulkhead connector, into the engine harness, and terminates at the PCM (the PCM commands the a/c compressor on and off via the A/C relay, and is triggered by a separate circuit that goes from pcm to HVAC controls in the dash)

The Washer pump and cruise control both travel via the engine bay harness and terminate at the driverside firewall bulkhead connectors.

And as requested, wiring diagrams for the engine harness and the PCM layout.