I did the fast idle override switch mod, here's how I did it.
I followed the above video from Enlisted Budget Videos.
What you're looking for is the first connector on the PCM.
Pin A12, on 97-01 XJ models it is going to be a gray wire, I'm not sure if it is the same on other years.
I spliced in a lead wire into this gray wire and connected it to a switch in the cab. (This photo does not show the heat shrink I used on the wire, but I did)
This is the temporary location of the fast idle switch. I mainly wanted to quickly rig this system up just to verify the functionality.
I will be rerouting the switch to a point yet to be determined on the dash.
With a flip of the switch the idle increases about 500 RPM.
Reasons to do this mod:
1. Higher coolant flow (good for warmer climates)
2. More alternator amperage flow (good for winching and off-road lights)
3. Faster engine warming (good for colder climates)
--Probably other advantages, but I haven't noticed them yet.
Mounted my GM under hood light I bought used off of eBay. Mine was missing the magnetic bottom. I will find a replacement soon online.
I have it wired into the OEM under hood light connection.
I upgraded the bulb to a very bright LED equivalent.
Old fluid - looks more like chocolate milk than Ps fluid
Ran new fluid out through return line until fluid ran clean.
Steering seems tighter, if that is possible.