I recently did this mod to my '07 F250 6.0l. It is very easy to do especially if you have factory upfitter switches:
http://www.fleet.ford.com/truckbbas/non-html/Q108.pdf
http://www.fleet.ford.com/truckbbas...s/2005/pto.html
Directions:
Remove the drivers side access panel (below the steering wheel) , remove the 4 bolts which hold the fuse panel. Pull the fuse box through the opening and leave it hanging.
Look for the UpFitter wire bundle :
Choose which switch you want to use. I used Aux-4 as it is one of the 10 amp circuits and only a signal voltage is required. Here is a list of wires:
Aux-1 Circuit No 1936 wire color: Orange/Lt. Green [30amp]
Aux-2 Circuit No 1933 wire color: Orange [30amp]
Aux-3 Circuit No 1934 wire color: Orange/Yellow [10amp]
Aux-4 Circuit No 1935 wire color: Orange/Lt. Blue [10amp]
Pull the black end off the chosen wire and strip off 1/4" of the insulation.
Crimp one end of one butt connector to this wire.
Prepare the 6" wire by stripping 1/4" of the insulation off both ends.
Crimp one end of the 6" wire to the open end of the butt connector used above.
Crimp another butt connector to the other end of the 6" wire.
Locate the top of the parking brake pedal (approximately 6" below the AUX wires).
Locate the SEIC/CASC wire bundle (about 12 wires with black ends)
Locate the solid ORANGE wire. There are many orange wires in this bundle, but most have a color tracer. You must use the SOLID orange wire.
Pull the black end off the SOLID ORANGE wire and strip off 1/4" of the insulation.
Insert the SOLID ORANGE wire into the open end of the butt connector attached to the 6" hookup wire.
This completes the electrical portion of this project. You need to replace the fuse box and access cover.
Testing
All the following are required to enable high idle:
Parking brake applied.
Foot off of service brake.
Vehicle in PARK (automatic trans.)
Foot off of clutch (manual trans.)
Foot off of accelerator pedal
Vehicle speed is 0 mph (stationary)
Brake lights functional
Engine at a stable base idle speed
Start your engine. Flip the UpFitter switch. The engine will idle up to 1200 rpm. If any of the required items changes state, the engine will go to its normal idle speed. If the item state is changed back to the required state, the idle will return to 1200 within 3 seconds.