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Note
When the vehicle is started or when several loads are switched on the display may briefly show the text mes-
sage “LO ” indicating the voltage drop.
1. Control panel warnings
The air conditioner control system features various functions to protect the unit or the battery. The activation of
a protective function is indicated on the display by the following codes.
7.5 Troubleshooting
Display messages
Message Description
Cause
Remedy
L O
The battery monitor signals under-
voltage. The compressor shuts off
immediately and the fans are shut off
after 20 to 30 seconds. The whole
system shuts off after 2 minutes.
The supply voltage is too low.
The battery capacity is insufficient to
operate the system.
➢
Short-term undervoltage: no action required.
➢
If the system shuts off: recharge the vehicle battery or
check if the battery monitor is set correctly.
H I
The system signals short-term or
permanent overvoltage.
Short-term overvoltage can occur
when large electrical loads are turned
off. Permanent overvoltage occurs
when the power supply voltage is
inadequate.
➢
Short-term overvoltage: no action required.
➢
If the display message “HI” is indicated for a longer
time: check the truck electronics. Make sure the voltage
supply is lower than 30 volts.
H O
The system signals a short-term
electrical overload and shuts the
compressor off.
The current power consumption of the
compressor is too high
➢
The short-term electrical overload is compensated by the
system by disabling the compressor. The compressor
will shortly after start up again.
The compressor is shut off. After 5
minutes the whole system is shut off.
The compressor (the cabin) is
excessively tilted.
➢
When the compressor is back in normal position, the
system can be switched on again.
