Function
The electric heater's power regulator switches the active PTC heater sections off after ignition terminal 15 is switched off.
If the input signals maximum heating capacity request (MHR = Max Heat Request), heater booster are enabled by the engine management (MM) or both have a logical LOW, the PTC heater booster stages are switched off.
Performance at undervoltage
The voltage is measured between terminal connection 15 and terminal connection 31 (ground).
The power regulator is equipped with an undervoltage detector. If a battery voltage of less than 11.5 V 1.2 V is detected which lasts longer than 0.5 seconds, all heater sections are switched off.
The cut-in threshold for undervoltage conditions is 12.0 V 1.2 V.
After an undervoltage is detected all stages are switched off in a time span of 50 ms one after the other.
The heating sections can be switched on again only after the undervoltage condition has been cleared.
Performance at overvoltage
The voltage is measured between terminal connection 15 and terminal connection 31 (ground).
The power regulator is equipped with an overvoltage detector. If a battery voltage greater than 17.2 V 1.2 V is detected that lasts longer than 0.5 seconds all heating sections are switched off after a maximum period of 6 seconds.
The cut-in threshold for overvoltage conditions is 16.7 V 1.2 V.
The heating sections can be switched on again only after the overvoltage condition has been cleared.
Referenced documents
- gf8370l4055va Temperature regulator microswitch, location/task/function
- gf8370l4058va PTC heater booster, location/task/design/function