Solar Cell: Testing and Inspection
Solar Roof, Checking
- Place vehicle in direct sunlight.
• If weather conditions are unfavorable, the solar sunroof can be illuminated using two commercially available 1000 W halogen lamps. A distance of at least 500 mm from the solar roof must be maintained. Make sure that all sunroof Solar Cells (C20) are illuminated completely and evenly so that the Solar Cells (C20) can supply sufficient electrical energy to drive the Fresh Air Blower (V2),
• Only an energy of 1.5 W is supplied when shining halogen lamps on the solar sunroof the Fresh Air Blower (V2) turns, but air flow is difficult to detect).
• Depending on the version, the actual power output of the Solar Cells (C20) voltage and current is displayed immediately after switching the ignition off in the Climatronic Control Module (J255) front A/C control head measured value block vehicle diagnosis, testing and information system VAS 5051 in the "Guided Fault Finding" function.
- Open the "center" instrument panel vents and close the remaining vents.
- Check setting on front A/C control head Climatronic Control Module (J255) or an MMI (Multi Media Interface), " solar mode" function must be set.
- Close sunroof.
- Switch off ignition (front A/C control head is blank).
A current of air can be felt from the dash panel vents (check by moistening palm of hand if necessary).
If no air flow can be detected:
- Check the DTC memory for the Climatronic Control Module (J255) front A/C control head and check its coding vehicle diagnosis, testing and information system VAS 5051 in the "Guided Fault Finding" function.
- Check the setting and adaptation on the Climatronic Control Module (J255) front A/C control head and the MMI. The " solar operation" function must be activated vehicle diagnosis, testing and information system VAS 5051 in the "Guided Fault Finding" function.
- Switch off ignition.
- Remove air intake housing with air flow door. Refer to=> [ Air Intake Shroud with Air Flow Door ] .
- Disconnect connector - A - from Fresh Air Blower Control Module (J126).
- Measure voltage between terminal - 2 - of solar roof) and terminal - 4 - (ground) at connector - A -.
• Specification: greater 12.3 V = depending on intensity of the solar radiation
- Connect a test lamp (12 V with maximum 5 W) between terminals - 2 - and - 4 - on connector - A -.
- Test lamp glows or lights depending on sunlight intensity.
• The solar cells must produce a voltage greater than approximately 12.3 V in order for the current to switch from the Fresh Air Blower Control Module (J126) to the Fresh Air Blower (V2). After the fresh air blower motor control module (J126) has produced a voltage greater than approximately 12.3V, the Fresh Air Blower (V2) will be actuated as long as the solar cells continue to provide a voltage of approximately 2 Volts or the ignition, auxiliary ventilation or auxiliary heating.
• Solar roof function is OK if test lamp glows or lights up. If fresh-air blower does not run, check Fresh Air Blower (V2) for freedom of movement and actuation of Fresh Air Blower Control Module (J126) by front A/C control head. If no fault is found, replace front A/C control head Climatronic Control Module (J255).
• If test lamp does not glow or light up, check wire connection to both terminals at sunroof cut-out. If no malfunction is detected, check the solar panel and => Body Exterior 60 Removal and Installation.
• Only a small energy of 1.5 W is supplied on shining halogen lamps onto solar roof fresh-air blower rotates but air flow is hardly recognizable.
• The current, which is sent from the sunroof Solar Cells (C20) to the Fresh Air Blower (V2), can be read in the measured value block depending on version of the Climatronic Control Module (J255) A/C control head. Move the vehicle into the sun with the sunroof closed or beneath two headlights as described above and then select the Climatronic Control Module (J255) A/C control head measured value block vehicle diagnosis, testing and information system VAS 5051 in the "Guided Fault Finding" function. After switching off the ignition, the current is then displayed which was sent from sunroof with Solar Cells (C20) when switching off the ignition and the brief period afterward.