I am interested in doing the high idle mod and I think I have got the hang of how to do it but I do have 3 questions.
-First off, I have read the tech and all the links but is there a way to install the high idle without having to involve applying the park brake, or did that method slip by me?
-Secondly, will doing this affect the original high idle or will it still work when the truck is cold?
-Last one. Do you have to use a special switch? Cause won't the high idle stay on with the swicth on, to where stepping on the brakes will slow it down, but letting off the brakes will speed it back up?

I hope you don't think my questions are dumb, I just like covering all my bases first. I hate mistakes!!

 

All Things Oval

1) All the conditions MUST be met before the high idle strategy will start. And yes engaging the parking brake is one of the conditions.

2) It does not effect the PCM cold strategy programming at all. They are two seperate and distinct actions.

3) You have to use a switch that supplies power to the Battery Charge Protect circuit or the PTO circuit, to actuate the High Idle strategy. The PTO circuit is designed to increase the engine speed to the proper RPM to drive the PTO correctly. The Battey Charge Protect circuit is designed to keep the batteries fully charged while the truck is sitting parked and running, such as and ambulance etc.

Yes when the switch for the High Idle mod is activated and ALL the conditions are met, the high idle strategy will begin. If you leave the switch on while you drive it will not go into the High Idle strategy unless ALL the conditions are met, (Parking Brake Set, Foot Off Brake Pedal, Transmission in Park).

Hope this helps

 

Your profile shows you have a 2003 so I assume you have a 6.0 liter Power Stroke and not the 7.3 liter.

For your reading pleasure:

Here's what you need to do. Look up under the dash between the steering column and the parking brake pedal. You will find a wiring harness behind the parking brake handle with a bunch of wires coming out of the harness that have the ends sealed off with charcoal?? colored heat shrink tubing.

If your not sure what you are looking at, look at the three wiring harnesses that come through the firewall to the left of the steering column shaft into the passenger compartment. The top harness is big, the middle harness is smaller than the top harness and the last harness closest to the floor is smaller still. The wire you are looking for comes out of the the middle harness where the harness routes up to the dash directly behind the parking brake handle.

One of these wires will be Light Blue with a Yellow stripe. This is the PTO function wire from the PCM. Placing battery power (battery positive) on this wire will command the PCM to raise the idle speed to 1200rpm as long as the transmission is in Park or Neutral and the service brake is released, meaning your foot is not on the brake pedal and the brake lights are not activated.

The other wire you are looking for is a White wire with a Light Blue stripe. This one is also easy to find. While looking under the dash direct your attention to the black OBD II datalink connector mounted to the lower part of the dash to the right of the steering column. This connector is what a service tech uses to hook up a scan tool which is needed to communicate with the vehicle PCM in order to check engine sensor data, engine trouble codes and to REFLASH your PCM. (You've heard about FLASHES haven't you???)

Anyway, look at this black connector and follow the wiring harness from the plug back up and inside the dash. Along the harness not too far up from the plug you will find the White wire with a Light Blue stripe included in the bundle of wires but the wire just stops short of the connector. Yes the wire does not plug into any one of the ports of the datalink connector.

This White wire with a Light Blue stipe is your positive battery source wire that you will connect to the Light Blue with a Yellow stripe PTO wire through a switch.

What I did was stop at Walmart's automotive section. I purchased some wire, a switch that has a Red illuminating paddle switch lever and some female crimp connectors and some butt connectors. (Note: The crimp connectors I purchased were manufactured or has 3M's name on the packaging and the plastic insulation on the connectors is heat shrinkable).

I used the wire and butt connectors to extend these vehicle wires so I could mount the switch under the dash to the right of the OBD II datalink connector. I crimped the female crimp connectors on the end of each wire so the wires could plug into the male terminals of the switch.

So far I have used two wires connected to the switch. The switch I purchased has three terminals. The last terminal is a ground connection that is used so that when the switch is turned on the switch paddle illuminates. (Note: The switch paddle lever on my switch is not bright enough to see during daylight and is dimmly lit and seen at night. Heck, with the idle speed at 1200rpm I don't think you will forget the switch is on).