Location
The hydraulic auxiliary drive (HAD) control unit (A83) is installed in the stowage space on the passenger side, on the rear panel of the cab.
W55.90-A003-08
A83 | Hydraulic Auxiliary Drive (HAD) control unit | A | Air admission |
Ventilation (A) prevents the accumulation of condensation in the hydraulic auxiliary drive (HAD) control unit (A83).
Task
The hydraulic auxiliary drive (HAD) control unit (A83) controls the hydraulic auxiliary drive and acts as an interface between the electronic components of the hydraulic auxiliary drive and the control units located on the driver's side. To this end, the Hydraulic Auxiliary Drive (HAD) control unit (A83) does the following:
Reading in of sensors and signals
Evaluation of input factors
Actuation of components
Reading in of sensors and signals
The Hydraulic Auxiliary Drive (HAD) control unit (A83) receives the input signals through the following connections:
Direct lines
Drive train CAN (CAN 4)
Direct lines
The Hydraulic Auxiliary Drive (HAD) control unit (A83) reads in the signals from the following components over direct lines:
Hydraulic pump angle sensor (HAD) (B110)
Manual transmission pressure sensor (HAD) (B111)
Forward pressure sensor (HAD) (B112)
Rearward pressure sensor (HAD) (B113)
Hydraulic fluid temperature sensor (HAD) (B114)
Oil level switch (HAD) (S95)
Drive train CAN (CAN 4)
The Hydraulic Auxiliary Drive (HAD) control unit (A83) also reads in the following signals over the drive train CAN (CAN 4):
Hydraulic auxiliary drive request via the hydraulic auxiliary drive (HAD) switch (S972)
On vehicles of model generation 4, sent by the modular switch panel (MSF) control unit (A43) (vehicles without code Z3L (Single SAM instead of SAM cabin and SAM chassis)) or by the single signal acquisition and actuation module (SSAM) control unit (A7a) (vehicles with code Z3L (Single SAM instead of SAM cabin and SAM chassis)) via the interior CAN (CAN 2), central gateway (CGW) control unit (A2), frame CAN (CAN 3) and drive control (CPC) control unit (A3).
On vehicles of model generation 5, sent by the advanced signal acquisition and actuation module (ASAM) control unit (A7) via the interior CAN (CAN 2), central gateway (CGW) control unit (A2), frame CAN (CAN 3) and drive control (CPC) control unit (A3a).
Load request from driver, from transmission control unit (TCM) (A5)
Evaluation of input factors
The hydraulic auxiliary drive (HAD) control unit (A83) evaluates the input factors and then actuates the corresponding components of the hydraulic auxiliary drive.
Actuation of components
The hydraulic auxiliary drive (HAD) control unit (A83) actuates the components of the hydrostatic auxiliary drive via the following connections:
Direct lines
Drive train CAN (CAN 4)
Direct lines
To operate the hydraulic auxiliary drive, the hydraulic auxiliary drive (HAD) control unit (A83) actuates the following components via direct lines:
Hydraulic pump solenoid valves (HAD) (Y67)
Forward solenoid valve (HAD) (Y67 y1)
Rearward solenoid valve (HAD) (Y67 y2)
Control pressure solenoid valve (HAD) (Y69)
Power hydraulics solenoid valve (HAD) (Y70)
Fan motor (HAD) (M25) over the cargo liftgate/fan relay (HAD) (K5 A31)
Drive train CAN (CAN 4)
The hydraulic auxiliary drive (HAD) control unit (A83) sends the "Display status/fault messages" request via the drive CAN (CAN 4), drive control (CPC) control unit (A3, A3a) and frame CAN (CAN 3) to the instrument cluster control unit (ICUC) (A1) (on vehicles of model generation 4 or on vehicles of model generation 5 with code J6A (Classic cockpit)) or to the instrument cluster screen (ICS) control unit (A153) (on vehicles of model generation 5 with code J6B (Multimedia cockpit) or code J6C (Multimedia cockpit, interactive)).
When all requirements for operation of the hydraulic auxiliary drive are fulfilled, the display in the instrument cluster control unit (ICUC) (A1) (on vehicles of model generation 4 or on vehicles of model generation 5 with code J6A (Classic cockpit)) or in the instrument cluster screen (ICS) control unit (A153) (on vehicles of model generation 5 with code J6B (Multimedia cockpit) or code J6C (Multimedia cockpit, interactive)) changes from white to blue.