GF67.10-D-0001H Heated Windshield, Function

GF67.10-D-0001H Heated Windshield, Function

- with CODE (F49) Heated windshield

Activation

Function requirements:
- Circuit 61 ON
- Stable idle mode
- Voltage not exceptionally high or low
Overvoltage is present when voltage > 15 V.
Undervoltage is present when voltage < 10.5 V.

The heated windshield (HFS) system is activated when the windshield heater button (N72/1s4) integrated in the UCP control unit (N72/1) is actuated. The UCP control unit stores the message "OBF_A1 FSB_HZG_EIN (HFS EIN)" on the controller area network bus, class B (interior compartment) (CAN-B).

The SAM control unit (N10) receives this message. Then it first checks the heating wire of the heated windshield (R22/2). Then the SAM control unit actuates the heated windshield via the heated windshield relay (K13/7). The SAM control unit returns the message "SAM_A4 HFS_AN (HFS EIN)" to the UCP control unit via the CAN-B and monitors this message.Activation of the HFS system is permanently indicated by the LED in the windshield heater button in the UCP control unit. If the UCP control unit does not receive feedback from the SAM control unit within t = 700 ms, the LED in the windshield heater button flashes for t = 5 s. If feedback is sent within t = 5 s, the LED in the windshield heater button is actuated permanently; otherwise, the LED in the windshield heater button goes out.

If the windshield heater button is pressed for longer than t = 25 s, the message "OBF_A1 FSB_HZG_EIN (HFS EIN)" is canceled, the HFS system is not activated and an error is stored.This is indicated by a LED flashing in the windshield heater button for t = 5 s. As soon as the windshield heater button is released for t = 1 s. the HFS system can be reactivated by again actuating the windshield heater button.

If the UCP control unit recognizes that voltage is too low before the HFS is activated, the message "OBF_A1 FSB_HZG_EIN (HFS EIN)" is CAN not transmitted and the LED in the windshield heater button flashes for t = 5 s.

Deactivation

The System HFS is deactivated, if the following prerequisites are present:
- The windshield heater button is actuated again.
- The maximum switch-on duration of t = 5 min. is reached.
- Status "Circuit 61 OFF" is present.

The UCP control unit transmits the message "SAM_A4 FSB_HZG_AUS (HFS AUS)" to the SAM control unit via CAN-B.Deactivation is indicated by the LED going out in the windshield heater button.

Temporary deactivation

The System HFS is temporarily deactivated if the following prerequisites are present:
- Idle is instable.
- Voltage is too low or too high.

If idle is instable, the message "LL_STBL_B = 0 (idle not stable)" from the CDI control unit (N3/20), with engine OM642, from the CDI control unit (N3/21), with engine OM642, or the ME-SFI control unit (N3/23), with engine M272, is stored on the CAN-B bus. The UCP control unit reads in this message and cancels the message "OBF_A1 FSN_HZG_EIN (HFS EIN)". If the UCP control unit reads the message "LL_STBL_B = 1 (idle stable)", it again transmits the message "OBF_A1 FSB_HZG_EIN (HFS EIN)" to the SAM control unit via the CAN-B bus. The temporary deactivation with instable idle is not indicated; the LED in the LED in the windshield heater button maintains its status.

If voltage is too low or too high, the UCP control unit cancels the message "OBF_A1 FSB_HZG_EIN (HFS EIN)".

Temporary deactivation when voltage is too low or too high is indicated by the LED flashing in the windshield heater button for t = 30 s.

If the threshold is exceeded when the voltage is too low, the UCP control unit again transmits the message "OBF_A1 FSB_HZG_EIN (HFS EIN)" to the SAM control unit via the CAN-B bus.Otherwise the message "OBF_A1 FSB_HZG_EIN (HFS EIN)" remains canceled, the LED in the windshield heater button flashes for t = 5 s and then goes out.