module. The module then calculates
voltage drop across the photoresistor
and determines the degree of solar
heating based on the change in voltage.
Voltage drop across the photoresistor
increases as solar radiation increases.
The IHKA control module processes the
photoresistor input every 10 seconds
and also checks it for plausibility based
on mapped values. Values outside the
limit indicate a malfunction and the solar
sensor signal is ignored by the module.
The IHKA module regulates interior
climate settings using the following:
Blower. The blower activation curve
is changed.
Ventilation. The opening angles of
air distribution flaps are changed.
Troubleshooting of the solar sensor is
carried out through the IHKA diagnostic
program incorporated in DIS or MoDiC.
The IHKA control module may set codes
indicating a short or an open circuit.
To access the solar sensor, remove the
trim in front of the main dashboard
panel, ahead of the dashboard vents.
Troubleshooting
Trouble with the heating and A/C system
can be broken down into one or more of
the following categories.
Mechanical problems
Control head malfunction
Blower motor malfunction
Heating and Air Conditioning
http://ebahn.bentleypublishers.com/BMW/3/E46/Repair%20Manuals/6...
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