GF83.70-P-4200GM STH Control Unit, Component Description

GF83.70-P-4200GM STH Control Unit, Component Description
- with CODE (228) Stationary heater

Component Identification:

Location
The STH control unit is integrated in the STH heater unit (A6), which is located in the left front fender behind the front wheel.

Component Identification:

Location
The STH control unit is integrated in the STH heater unit, which is located in the right fender at the top behind the front wheel.



Task
The STH control unit has the following tasks:
^ Reading in of signals
^ Evaluation of input factors
^ Actuation of components

Reading in of signals
The input factors are read in with the following connections:
^ Direct line
^ Interior CAN

Direct line
The following signals are read in via a direct line:
- STH radio remote control receiver (A6/1)
- Temperature sensor (A6b1)
- Thermal fuse (A6f1)
- Glow pin unit flame monitor (A6r4)

If the temperature of T = 125 �C is exceeded in the STH heater unit, the thermal fuse detects overheating and triggers the heater unit fault run-on process for approx. t = 120 s followed by fault interlock.

Interior CAN
The following signals are read in with interior CAN by the:
by the EZS control unit (N73)
- Circuit status
From the upper control panel control unit (N72/1):
- Status of STH switch (N72/1s30)
by the instrument cluster (A1):
- Preselection time
By the AAC [KLA] control and operating unit (N22) (without code (581) Comfort automatic air conditioning) or at the comfort AAC [KLA] control and operating unit (N22/7) (with code (581) Comfort automatic air conditioning)
- Ventilation or heating
- Ambient temperature

Evaluation of input factors
The input factors that have been read in are evaluated by the integrated microprocessor and the relevant components are then actuated.

Actuation of components
Components are actuated with the following lines:
^ Direct line
^ Interior CAN

Direct line
The following components are actuated via a direct line:
- STH radio remote control receiver
- Circulation pump (A6m1)
- Combustion air blower (A6m2)
- Glow pin unit flame monitor
- Fuel preheating system (A6r5) (with diesel engine)
- Auxiliary heater metering pump (M46/1)
- STH switchover valve (Y16)

Interior CAN
The following components are actuated with the interior CAN:
By the upper control panel control unit:
- STH switch

Variants
- Gasoline version
- Diesel version