Operation of Solar Roof
Operation Of Solar Roof
NOTE:
- Solar mode is only possible with sun roof closed or tilted (solar energy converted into electrical energy by solar roof - C - is supplied to vehicle electrical system via contacts - A - (at front edge of sun roof) and - B - (at sun roof frame)).
- Solar mode is not possible with ignition on and in auxiliary heating/auxiliary ventilation mode (Fresh Air Blower Control Module J126 interrupts link between solar panel and Fresh Air Blower V2)
- If solar operation of Fresh Air Blower is not required, function can be deactivated at Climatronic Control Module J255 or in MMI (Multi Media Interface) Owners manual.
- Measured value block of Climatronic Control Module J255 (display group 044) indicates operating time in hours of Fresh Air Blower V2 in solar mode "Guided Fault-Finding" function of Diagnostic Operation System VAS 5051.
- Design of Fresh Air Blower Control Module J126 is such that in solar mode, Fresh Air Blower V2 is only actuated given generation of sufficient operating energy by solar cells (at present, minimum voltage with Fresh Air Blower V2 actuated must be greater than 2 V).
- The energy supplied by the Solar Cells C20 is transferred via the Fresh Air Blower Control Module J126 directly to the Fresh Air Blower V2. The Fresh Air Blower converts the electrical energy generated into blower power.
- On vehicles with no solar panel, all air conditioner control motors come to a halt in their instantaneous position when ignition is switched off. Ventilation of the passenger compartment in solar mode does however require the fresh-air and recirculation flaps to be set to "fresh-air mode". On vehicles with solar roof, the Climatronic Control Module J255 is therefore informed that solar cells are installed by way of the coding. The Climatronic Control Module J255 then moves the flaps in the air conditioner unit to the "fresh-air mode" position after switching off ignition.
- The Fresh Air Blower Control Module J126 checks the voltage at the input of the solar cells at regular intervals when the ignition is off (no signal detected by Climatronic Control Module J255) and converts the voltage generated by the solar cells in such a manner that the Fresh Air Blower runs at the maximum possible speed if sufficient solar energy is being generated.
- The electrical energy supplied by the solar roof is approx. 12 W with a sunlight exposure of 500 W/m2:
- 500 W/m2 (sunlight exposure) x 0.21 m2 (sun roof solar area) x 0.13 (efficiency of Solar Cells C20) x 0.9 (efficiency of Fresh Air Blower Control Module J126)
- Contacts - A - and - B - (at sun roof and sun roof frame) for transferring the electrical energy generated must be clean and free from normal lubricant.
- If necessary, contacts - A - and - B - can be coated with a small quantity of contact grease (electrically conductive preservative and lubricant available from electronics dealers).
Checking operation of solar roof
- Move vehicle into the sun.
NOTE: If weather conditions are not suitable, shine two commercially available 500 W halogen lamps for example onto solar roof, maintaining a distance of 500 mm from solar roof.
- Open "center" dash panel vents and close all other vents.
- Check setting at Climatronic Control Module J255 or MMI (Multi Media Interface); "Solar mode" function must have been set.
- Close sun roof.
- Switch off ignition (front operating and display unit blank).
A current of air can be felt from the dash panel vents (moisten palm of hand to check if necessary).
If no current of air can be felt:
- Check DTC memory of Climatronic Control Module J255 and check coding of front operating and display unit "Guided Fault-Finding" function of Diagnostic Operation System VAS 5051.
- Check setting (and if necessary adaptation) at Climatronic Control Module J255 and MMI ("Solar mode" function must have been activated).
- Switch off ignition.
- Remove intake housing with air flow flap
- Unplug connector - A - from Fresh Air Blower Control Module J126.
- Measure voltage between contact - 2 - (of solar roof) and contact - 4 - (ground) at connector - A - .
- Specification: 8....12 V DC (depending on sunlight intensity)
- Connect test lamp (12 V, max. 5 W) between contacts - 2 - and - 4 - at connector - A - .
- Test lamp glows or lights (depending on sunlight intensity).
NOTE:
- Solar roof function is OK if test lamp glows or lights. If fresh air blower does not run, check freedom of movement of Fresh Air Blower V2 and actuation of Fresh Air Blower Control Module J126 by front operating and display unit. Replace Climatronic Control Module J255 if no malfunction is found.
- If test lamp does not glow or light, check wiring to the two contacts at the sun roof opening. If no malfunction is found, replace solar panel
- Electrical energy supplied is only approx. 1.5 W on shining halogen lamps onto solar roof (fresh air blower rotates but air flow is hardly perceptible).