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Home >> Mercedes Benz >> 2010 >> GL550 >> Repair and Diagnosis >> Accessories & Equipment >> Interior/Illumination Lights >> Charging, Control Panel/Cluster, Data Bus, Fuses/ Relays, PARKTRONIC, Sensors & Switches - 164 Chassis >> Basic Knowledge >> Upper control panel control module component description - GF54.21-P-6040GZ

Upper control panel control module component description - GF54.21-P-6040GZ

MODEL 164.1 /8 with CODE (489) Airmatic (air suspension with level adjustment and adaptive damping system ADS) except CODE (430) Offroad package 

Shown on model 164.8 

Location 

The upper control panel control unit is located in the center console.

Fig 1: Identifying Upper Control Panel Control Unit - Shown On Model 164.8
G05258999Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Task 

Scanning the following switches: 

Reading in the following function indicator lamps: 

Voltage supply and reading in of data: 

Function 

ESP OFF switch 

The ESP Off switch can be used to switch the anti-slip control of the "Electronic Stability Program" on and off. The function requirements for this switch is circuit 15 "ON". The function of the ESP systems is indicated in the instrument cluster (A1).

Level control switch 

Function requirements: 

Switch actuations enable the driver to choose between a highway level and a raised level. The vehicle is in the highway level state (no function indicator). If the vehicle is lifted to the raised level, the LED in the switch flashes on and off. When the level is reached the LED remains constantly on. The last stage selected with function indicator is active once the engine is started again.

Hazard warning system switch 

Pressing the hazard warning system switch wakes-up the upper control panel control unit from its "Sleep mode" and the hazard warning system function is activated. The message is sent cyclically (every 100 ms) until the function is deactivated by pressing the hazard warning system switch again. The flashing function illumination of the hazard warning system switch is triggered by the CAN message of the rear SAM control unit (N10/8). There is no faster flashing of a defective indicator lamp for the hazard warning flasher system. As soon as the hazard warning flasher function is activated the switch and controls illumination for the hazard warning system switch is switched off. The function illumination of the hazard warning system is not dimmed.

IMPORTANT The selected function is confirmed when the indicator lamps (LEDs) light up. The pulse to light up is sent by each respective control unit.

PTS OFF switch 

The Parktronic system is activated or deactivated via the PTS OFF switch. If the switch is actuated, the upper control panel control unit sends a signal to the PTS control unit (N62) via CAN-B. The PTS control unit then sends a message requesting actuation of the status LED in the PTS OFF switch back to the upper control panel control unit.

Left front HS [SIH] switch and right front HS [SIH] switch 

The heated seats have 3 stages. One-time actuation of the SIH switch activates stage 3 of the heated seats (all 3 red LEDs light up). Further actuations switch to stage 2 (the two lower LEDs go on), to stage 1 (the lowest LED goes on), or the heated seats are switched off (no function indicator). The function requirements for this switch is circuit 15R "ON". Each press of the left front HS [SIH] switch and right front HS [SIH] switch is sent by the upper control panel control unit over the CAN-B.

Left front seat ventilation switch and right front seat ventilation switch (only model 164.8) 

When the left front and right front seat ventilation switch is actuated, the upper control panel control unit sends a signal to the HS [SIH], seat ventilation and steering wheel heater control unit (N25/7) via CAN-B.

The switch is used to switch the seat ventilation in the respective seat on and off, and also to control the ventilation output. The level of ventilation output is displayed by indicator lamps in the respective switch.

Downhill Speed Regulation switch 

The driver can switch the DSR on and off using the Downhill Speed Regulation switch. A red LED integrated into the switch indicates whether the function is active or not. Downhill Speed Regulation is an aid for driving down hills with an adjustable speed that can be set between 4 and 18 km/h.

Offroad program switch 

The offroad program switch is used to adjust the dynamic characteristics of the vehicle in order to optimize traction and forward propulsion in offroad operation (e.g. by changing the shifting behavior of the automatic transmission).

STH switch 

The function of the STH switch depends on the current terminal status. Whenever the stationary heater is activated, the AAC [KLA] control and operating unit (N22) receives a query as to whether heating or ventilation is required. The currently active function is displayed by an indicator lamp in the STH switch as follows:

Function with terminal 15R OFF 

If the switch is actuated, the system is switched on or off immediately. When switched on, the upper control panel control unit sends a signal to the heater booster control unit (N33/2). The latter then sends the command to switch on the stationary heater to the AAC [KLA] control and operating unit.

IMPORTANT Since the AAC [KLA] control and operating unit needs time to decide whether heating or ventilation is required, the red indicator lamp is activated by the upper control panel control unit immediately after the switch is actuated.

The AAC [KLA] control and operating unit permanently switches the indicator lamp to the appropriate color depending on whether heating or ventilation is required.

Function with terminal 15R ON 

If the switch is actuated for less than 2 s with the system switched off, the timer menu is shown in the multifunction display (A1p13) in the instrument cluster. The system will be activated if the switch is pressed for a longer time.

If the system is already activated, it is switched off again immediately without the timer menu being displayed.

Comfort/Sport switch (ADS) 

The driver can program the damping level as desired using the Comfort/Sport switch (ADS):

  1. "AUTO"  Skyhook mode
  2. "SPORT"  Firm damping
  3. "COMFORT"  Soft damping

In the "SPORT" setting the upper LED goes on and for the "COMFORT" setting the lower LED goes on. If the vehicle is in the "AUTO" mode nothing is displayed in the Comfort/Sport switch (ADS).

Discrete inputs: 

Discrete outputs: 

Voltage limit: 

The operating voltage is between 12 and 14 V.

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