Wrangler 4WD L4-150 2.5L VIN P MFI (1998)
Fig. 2 Power Distribution Center (PDC)
The A/C relay is located in the Power Distribution Center (PDC). The PDC is located in the engine compartment (Fig. 2). Refer to label on PDC
cover for relay location.
The Powertrain Control Module (PCM) activates the A/C compressor through the A/C clutch relay The PCM regulates A/C compressor operation
by switching the ground circuit for the A/C clutch relay on and off.
When the PCM receives a request for A/C from A/C evaporator switch, it will adjust Idle Air Control (IAC) motor position. This is done to
increase idle speed. The PCM will then activate the A/C clutch through the A/C clutch relay The PCM adjusts IAC stepper motor position to
compensate for increased engine load from the A/C compressor.
By switching the ground path for the relay on and off, the PCM is able to cycle the A/C compressor clutch. This is based on changes in engine
operating conditions. The PCM will also de-energize the relay if coolant temperature exceeds 125°C (257°F).
Auto Shutdown (ASD) Relay-PCM Output
AUTO SHUTDOWN (ASD) RELAY-PCM OUTPUT
Fig. 2 Power Distribution Center (PDC)
The Auto Shutdown (ASD) relay is located in the Power Distribution Center (PDC) (Fig. 2).
The ASD relay supplies battery voltage to the fuel pump, fuel injector, ignition coil and both oxygen (O2S) sensor heating elements. The ground
circuit for the coil in the ASD relay is controlled by the Powertrain Control Module (PCM). The PCM operates the ASD relay by switching the
ground circuit on and off.
Battery Temperature Sensor-PCM Input
BATTERY TEMPERATURE SENSOR-PCM IN PUT
Provides a signal to the PCM corresponding to the battery temperature.
Battery Voltage-PCM Input
BATTERY VOLTAGE-PCM INPUT
