Sliding Roof/Solar Roof - Volkswagen PASSAT - YEAR 2001 Manual

The Electrics

Sliding roof/solar roof

The solar roof generates electric current via
integrated solar cells. This powers the fresh air
blower, which cools down the vehicle interior to
approx. 20°C. The system operates when the
ignition is off and when the sliding roof is open or
tilted.
A DC/DC converter is mounted
on the underside of the sliding roof.
The DC/DC converter serves the purpose of current/
voltage adaptation between the solar generator
(solar module) and the blower. It converts the high
voltage and low current intensity which the solar
module supplies into a low voltage and high current
intensity since the blower motor requires a very high
starting current.
251_035b
+ from blower control
Terminal 15
Solar cell
isolation relay
J309
Earth
50
An electronic circuit in the DC/DC converter
only enables the fresh air blower motor if the
voltage is above a threshold value of 2 V. This
avoids damage to the blower bearings.
When the ignition is off, the contact is in this position.
This allows the fresh air blower to receive its voltage
supply from the solar roof.
Solar cell contact
switch
F288
Solar roof control
unit
J355
Fresh air blower V2
Contact switch in
sliding roof F289
Solar cells C20
251_035
251_040