Comanche 4WD L4-150 2.5L VIN E TBI (1989)
A/C Signal: Description and Operation
These input signals indicate to the ECU that air conditioning switch is in the ON position, and that a signal needs to be sent to the air conditioning clutch
relay to engage the compressor clutch. Before the A/C clutch can be engaged, the ECU will increase the engine speed to ensure that the added load of
the A/C compressor will not kill the engine.
The ECU increases the idle through both the A/C select and A/C request controls. The ISA motor is extended via the A/C select circuit, and the injector
pulse width is increased via the A/C request circuit.