3. Extended Idle Switch wiring is as follows (per the FSM):
Pin #1 - Ground (Black on the OEM Ext Idle pigtail)
Pin #2 - Idle Actuator (Grey on the OEM Ext Idle pigtail)
Pin #3 - Fused Ignition Switch Output (RUN) (Dark Blue w/ White stripe on the OEM Ext Idle Pigtail)
Pin #4 - Fused Panel Lamps Dimmer Switch Signal (Orange on the OEM Ext Idle Pigtail)
Unless you managed to score a pigtail from a Police Package XJ, your pigtail will not match up. I chose to use the Defrost pigtail since the #1 & #4 (Black & Orange) leads are the same as the original pigtail. Here's the easiest way to wire it all up:
Connect Ext Idle Switch Pin #1 to Fog Lamp Switch Pin #4 (Black)
Connect Ext Idle Switch Pin #2 to your wire leading to A12 on the PCM
Connect Ext Idle Switch Pin #3 to A/C Heater Control Pin #2 (Dark Blue / White stripe)
Connect Ext Idle Switch Pin #4 to Fog Lamp Switch Pin #1 (Orange)