BMW 1999-2005 M3 Service Manual page 1132

Heating and Air Conditioning
14 of 22
http://ebahn.bentleypublishers.com/BMW/3/E46/Repair%20Manuals/6...
On hard top:
Rear relay is energized.
Power to hard top window is
supplied through connector strip on
hard top lock.
On convertible top:
Rear relay is energized. It powers
front relay.
If convertible top control module
(CVM) signals that convertible top is
locked to windshield frame, front
relay powers rear window heater
grid.
If convertible top is lowered, a
signal from CVM to front relay
prevents heated top operation.
Front relay also signals sound
system to switch stereo sound ON
when top is up, stereo sound OFF
when top is down.
Solar sensor
The purpose of the solar sensor is to
detect and relay information about the
amount and intensity of solar heating to
the IHKA control module. The settings of
the climate control system are changed
to compensate for this additional
influence.
The solar sensor consists of a
photoresistor installed in the right
defroster outlet and a short harness.
The solar sensor receives power (5 volts)
and ground from the IHKA control
2/25/2009 11:16 PM