GF54.30-P-4001PP Coolant/Washer Fluid Level Voltage Coding, Function

GF54.30-P-4001PP Coolant/washer Fluid Level Voltage Coding, Function
- MODEL 203.0 /2 /7 up to 23.4.04

Diagram for low washer fluid level






A Front SAM control unit with fuse and relay module (N10/1)
ADC Analog/digital converter
S41 Coolant level indicator switch
S42 Windshield washer fluid level indicator switch

The coolant level indicator switch (S41) and windshield washer fluid level indicator switch (S42) are connected in series and are read in by the front SAM control unit with fuse and relay module (N10/1).

Voltage coding
Switch (s1) and switch (s2) are connected in parallel for voltage coding of resistor (r1) and resistor (r2); the values of resistor (r1) and resistor (r2) must be different. When the switches (s1, s2) are open, these resistors (r1, r2), together with resistor (r3) of the front SAM control unit with fuse and relay module (N10/1), form a voltage divider, which is supplied with the constant voltage (u). The voltage (ue) at the input of the front SAM control unit with fuse and relay module (N10/1) is thus dependent on the positions of switch (s1) and switch (s2) and the values of the resistors (r1, r2, r3). Each switch combination (s1, s2) gives a different voltage value (ue) at the input of the front SAM control unit with fuse and relay module (N10/1).

Evaluation
The voltage (ue) is applied at the input of the analog-to-digital converter (ADC) of the front SAM control unit with fuse and relay module (N10/1). The analog-to-digital converter (ADC) converts the analog voltage into a digital value. The processor compares the digitized values to the threshold values stored in memory and, if necessary, passes an appropriate message "CHECK COOLANT LEVEL" and/or "CHECK WASHER FLUID LEVEL" on the class B (passenger compartments) controller area network bus (CAN-B). The instrument cluster (A1) reads in this information and controls the multifunction display (A1p13) accordingly.

The messages can be acknowledged by pressing the trip odometer reset button (A1s3) on the instrument cluster (A1).

Switch status and messages
With the coolant level indicator switch (S41) and the windshield washer fluid level indicator switch (S42) there are 4 possible switch combinations which result in the following displays on the multifunction display (A1p13):
- If the coolant level indicator switch (S41) is open and the windshield washer fluid level indicator switch (S42) is open, a message does not appear on the multifunction display (A1p13).
- If the coolant level indicator switch (S41) is open and the windshield washer fluid level indicator switch (S42) is closed, the message "CHECK WASHER FLUID LEVEL" appears on the multifunction display (A1p13).
- If the coolant level indicator switch (S41) is closed and the windshield washer fluid level indicator switch (S42) is open, the message "CHECK COOLANT LEVEL" appears on the multifunction display (A1p13).
- If the coolant level indicator switch (S41) is closed and the windshield washer fluid level indicator switch (S42) is closed, the message "CHECK COOLANT LEVEL" appears on the multifunction display (A1p13). The message "CHECK WASHER FLUID LEVEL" has a lower priority and is therefore not displayed straight away.