Heating wiper support, function - GF82.30-P-2003FQ
MODEL 218
Function requirements, general
- "Engine running" or "drive train operational" signal on
- Outside temperature T < 5 °C
The CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) sends the "Engine running" or "Drivetrain operational" signal over the chassis CAN (CAN E) (up to 28.2.13) or chassis CAN 1 (CAN E1) (as of 1.3.13) to the front SAM control unit with fuse and relay module (N10/1).
Heated wiper park position, general
Heating the wiper park positions at low outside temperatures prevents the wiper blades from freezing to the windshield.
Heated wiper park position function sequence
The front SAM control unit switches on the wiper park position heater (R2/10) when the engine is running and at an outside temperature of T < 5 °C via the wiper park position heater relay (N10/1kL).
The following variables are considered here:
- Engine coolant temperature
- Ambient temperature
- Vehicle speed
- Sun angle
- Windshield wiper operation
Engine coolant temperature:
The engine coolant temperature is recorded by the coolant temperature sensor (B11/4). The CDI control unit or the ME-SFI [ME] control unit reads in the coolant temperature sensor signal directly, calculates the engine coolant temperature, and sends this for vehicles up to 28.2.13 over the chassis CAN to the instrument cluster (A1) and the front SAM control unit. In vehicles as of 1.3.13, the CDI control unit or the ME-SFI [ME] control unit sends the engine coolant temperature over chassis CAN 1 to the front SAM control unit, and over chassis CAN 1, the front SAM control unit and chassis CAN 2 (CAN E2) to the instrument cluster.
Outside temperature:
The outside temperature is detected by the outside temperature sensor (B14). The front SAM control unit directly reads in the signal of the outside temperature sensor, calculates the outside temperature and sends it to the instrument cluster over the interior CAN (CAN B). The instrument cluster calculates the outside temperature to be displayed, taking the vehicle speed and the heat dissipated from the engine into account, and sends this via interior CAN to the front SAM control unit.
The vehicle speed is calculated by the instrument cluster itself.
If the front SAM control unit does not receive an outside temperature value from the instrument cluster, it uses the outside temperature value it calculated itself.
Sun angle:
The sun sensor (B32/3) detects the level of solar radiation. The automatic air conditioning control and operating unit (N22/7) reads in the data of the sun sensor directly and sends the data over the interior CAN to the front SAM control unit.
Windshield wiper operation:
The wiper request is defined by means of the switch position of the combination switch (S4). The steering column tube module control unit (N80) reads in the switch position of the combination switch directly and sends this via chassis CAN (up to 28.2.13) or chassis CAN 1 (as of 1.3.13) to the front SAM control unit. The front SAM control unit reads in all the relevant information and actuates the wiper park position heater accordingly.
If the weather is currently precipitation free (as detected by sun sensor), when in continuous heating mode with precipitation, and to avoid any glass damage caused by overheating, the maximum operating time of the wiper park position heater is t = 25 min. If the outside temperature rises to a value of T > 15 °C, the front SAM control unit switches off the wiper park position heater.
The wiper park position heater is switched off automatically under the following conditions:
- No wiper request for t > 25 min. and engine coolant temperature of T < 70 °C
- Engine coolant temperature of T < 70 °C and the sun sensor signals "solar radiation through the windshield". The sun sensor information is not evaluated until after t = 15 min.
- No wiper request for t > 15 min and engine coolant temperature of T > 70 °C
If a wiper request is then pending, the wiper park position heater is activated again. If the windshield has only been washed, the front SAM control unit then switches off the wiper park position heater after t = 10 min.
- When the vehicle is stationary, the wiper park position heater is switched off after t = 10 min.
| Electrical function schematic for heated wiper park position | PE82.35-P-2053-97XAA |
| Overview of system components, wiper system (WSA) | GF82.30-P-9997FQ |