I have the "official" wiring manual for my vehicle, which apparently was wired for PTO function (which kicks up rpm).
The G/Y wire on mine Was the PTO wire.

If yours also was wired for PTO, perhaps you can research which wire that will be.

It was rather frustrating for me (wire colors different from others), so I took that chance of popping a fuse.
It very well may be, that your vehicle does not support this feature.

 

White blue above OBD II port, look for that tag wrapped around the wires in pic #1 and G/Y above and behind the fuse box. Both are just blunt wires, worst is pop a fuse. Mine looked grey/yellow near the e-brake, maybe I'm seeing differently...

 

I thought G/Y was late 04+

I tried all 3 blunt ended wires and nothing. I guess they left that wire out on Excursions

 

should be 4 of them.... at least on the truck there was 4

 

Iv got 3 smaller wires and 4 larger solid colored wires

I find it hard to believe they would leave that one wire out on just Excursions. But not impossible I guess

 

Sure you didn't miss one in that bundle... mine were wrapped up pretty good, had to get in behind the fuse box and dig them out. They could have... anybody else have it done?

 

The end of the solid color wires should be in the engine compartment, near the firewall on driver side.

My high idle mod were the same as pictured in post #3. Mine is a late build 04.

https://www.ford-trucks.com/forums/9...ml#post9250472

 

Mine works as "advertised" (even though the dealership diesel tech said it couldn't be done).
Wire colors/location same as yours. Must be an 03 - early 04 thing.

 

High idle mod on Excursion.
https://www.ford-trucks.com/forums/7...-idle-mod.html

 

Aha! So the wires really not there! Thank you for posting that!

 

Didn't realize that wasn't available on X's. Thanks for posting that up.

 

Learned something myself.... thank you

 

Big thank you to Mr Axlerod. High idle is installed and working like a charm. It just took A LOT longer than a standard pick up lol

 

It's still better than a brick on the pedal.

 

That woulda been way easier lol. But flipping a switch is nice!