I have been looking around at all the million ways you can do this and I came up with another way that seems pretty spiffy. Here's what I have come up with.

First off, in the cab you need 3 single pole single throw switches, which are the simplest form of a switch you can get.

Here is a pic of one.

You install all of those, and hook one side of each switch to a good ground inside the cab. Now run the other side of each switch all outside into the engine bay. One switch will fool the coolant, one switch will turn on high idle, and one will turn on 3 cyl idle. The positive side of each relay is "always on" positive, so you can jumper from one relay to the next. The negative is the switched part.

Now you need 3 relays. The ones I found are as common as pocket lint so are $2 a piece.

These are the ones you need. http://www.parts-express.com/pe/showdetl.cfm?partnumber=330-073&source=googleps

Any auto parts store should have them.

Alright so the contacts on the relays look like this. Labeled exactly the same.

To make the ECT fooler, this is how it is wired.

To do the high idle and 3 cyl relays you do it like this. You might think it goes through the IAT sensor and the 56k resistor when you turn it to 3cyl idle, well it does, but as far as I can tell, 56k or more will do the same thing. So the 56k and the IAT sensor resistance will add up, but produce the same effect.

This way you should only have 3 wires leaving the cab since you should be jumping ground from a place inside the cab. You put the relays somewhere outside the cab like next to the ECM.

So the operation is like this. You hit the ECT switch and now it thinks it is 123F. If you hit the high idle switch it fools IAT into thinking its 28F. If you hit the 3cyl switch it fools it into thinking it is 13F or below since it adds IAT sensor into the equation on that switch. the IAT foolers must only be on separately. If you turn them both on, it will add up all the resistors and do 3cyl.

This means there is no IAT fooler switch or high idle mode switch. There is only a switch for high idle that you turn on or off, and a switch for 3cyl which you turn on or off. The relays are wired so that the normally closed position is the stock position, so if the relays mess up, it will be just like stock. It is also good because they don't need any power to be remain closed. Only when they energize do they switch to the resistors.

The only long wires you should have are the 3 from the switches and the 1 positive wire. You jumper the positive to the other 2 relays. If you mount the relays by the ECM anyways, that will make a short trip to it and you can even splice into the ECT/IAT wires as they go into the ECM.

Operation

Cold Engine Start (Coolant <140°F - Outside Temp > 32*F)

Turn on the high idle switch. Now start your engine. With in about 2 minutes the high idle should start. Once the high idle starts turn off the high idle switch and allow the ECM to monitor the IAT temperatures. As the engine warms up to 170°F it will cancel on its own and idle normally from that point on.

Cold Engine Start (Coolant <140°F - Outside Temp < 32*F)

Turn on the 3 cyl switch. Now start your engine. With in about 2 minutes the high idle should start once it get to 1,200 PRM's the 3 cylinder mode with begin. Once the high idle starts turn off the 3 cyl switch and allow the ECM to monitor the IAT temperatures. As the engine warms up to 170°F it will cancel on its own and idle normally from that point on.

Warm Engine Start (Coolant 140°F-170°F)

You can start the high software with a warm engine. At this point you need to use both the ECT switch and high idle or 3cyl switch. Select the proper idle switch for your weather conditions as in cold start procedure. Once the high idle starts turn off the foolers and allow the ECM to monitor both ECT & IAT temperatures. As the engine warms up to 170°F it will cancel on its own and idle normally from that point on.

Forced High Idle

Turn on both the ECT fooler and the high idle switch. Start the engine and allow the high idle to start. Once the high idle starts turn off the high idle switch but leave the ECT fooler on. This will allow a forced high idle that never ends. To cancel it just turn off the ECT fooler and it will cancel.

So what do you guys think? I can't test out my idea until I decide to get a 24V

Get a pic or something of the switch you have. I want to be sure of what I am working with. I will see what I can figure out since you want all the features. Single switch high idle is easy but all the features make it a little harder.

Yeah that's true, but in my opinion, just not practical.

here's a link: http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=m2044b2b1w01

Yeah that's the one I posted about. At least we are on the same page now. Let me see if there is a way to wire it to work.