Inputs and Outputs

Five electrical connectors provide the interface between the automatic temperature control (ATC) module and the vehicle/heater assembly wiring.

The automatic temperature control (ATC) receives all information from EMS via BCM. If the signal is controller area network (CAN) based and it has an associated QF (Quality Factor), then this is what will be stored in random access memory (RAM), so that it will be possible to log via CCP. If the signal is controller area network (CAN) based and lacking a QF, or if the signal is hardwired, then the HVAC s/w must determine the applicable QF value and report this via diagnostics or CCP when requested.

If a fault develops and QF = 0 at start up, then the evaporator sensor signal is used until QF >= 2.

If evaporator temperature sensor is faulty, then a default of 10^o C will be used until either sensor QF >= 2.

If ambient temperature sensor QF >= 2 at start up, then during session QF drops to < 2, then the last known "good" value will be used until QF >= 2 again.