Have OBA, A winch, or would just like a higher idle for other purposes? Here is the mod for you.
The "Extended Idle" switch was an option on the police issue Cherokees. It is said to be there to kick up alternator output for high demand things such as lights and AC, and to keep the cooling system running a little quicker.
This mod is very simple, and if you have your stuff together it will only take about half an hour.
This Writeup will not have many pictures, since many people will have different places to put their switches.
Required tools: Electrical tape, Philips Screwdriver, Wiretap Connector, Wire, Switch, Dremel or something to cut the Dash.
1: Pull the first plug on the ECU, it is the black one, furthest to the left.
2: Find Pin A12. It is the 2nd row down, on the left. It should be a gray wire, if you have a 97.
3: Cut the electrical tape wrapping and get the gray A12 wire by itself.
4: Use your wiretap connector to splice in your wire:
5: Run your wire into the passenger compartment. There is a hole that the hood release cable comes out of. This is what I used.
6: Pull your wire into the jeep and decide where you want your switch. I decided to mount mine along with the other switches in the dash.
7: Cut your panel where you want the switch. Be sure to get the dimensions correct, you dont want a big ugly hole. Dremel works good for this, but be careful.
7: Hook the wire from the ECU to one side of your switch.
8: Hook the other side of your switch to a ground source. I used a wire to the Cigarette lighter ground.
9: Insert switch, Put Dash back together.
10: Test it out. Start your jeep and flip the switch. Your idle should increase to ~1000 RPM and stay there until the switch is turned back off.