Solar Roof Electrical Test
Solar Roof Electrical Test
=> [ Solar Roof, Checking Function ]
• Solar ventilation function only works when the sunroof is either closed or in the raised position. The solar sunroof converts the solar energy into electrical energy which then passes into the vehicle electrical system via terminals - A - (on the front of the sunroof) and terminals - B - (on the frame of the sunroof).
• Solar operation is not possible with ignition switched on and with parking heater/parking ventilation running (Fresh Air Blower Control Module (J126) breaks the connection between solar roof and Fresh Air Blower (V2)).
• On vehicles without sunroof, all A/C system control motors remain standing in their current positions at the moment when the ignition is switched off. However, in order to ventilate the vehicle interior when the system is in solar ventilation mode, the fresh air/recirculated air door must be in the " fresh air" position. Therefore on vehicles with solar roof, the A/C control head Climatronic Control Module (J255) sends via the coding the indication that the vehicle is equipped with a sunroof with Solar Cells (C20). A/C control head Climatronic Control Module (J255) then moves the doors on the heating and A/C unit into the "fresh air" position after ignition is switched off.
• The energy supplied by the Solar Cells (C20) is conveyed directly to the Fresh Air Blower (V2) via Fresh Air Blower Control Module (J126). The fresh air blower (V2) converts the generated electrical energy into blower output.
• With the ignition switched off (no signal detected from the Climatronic control module (J255) A/C control head), the fresh air blower control module (J126) checks the voltage at the input of the solar cells in regular intervals and converts the voltage generated by the solar cells in such a way that the fresh air blower (V2) runs at the highest possible speed when there is sufficient solar energy.
• The electrical energy transferred from the Solar Cells (C20) at a solar radiation level of 500 W / m2 is approximately 12 W:
500 W / m2(solar irradiation) x 0.21 m2 (solar cell surface area on sunroof) x 0.13 (efficiency of Solar Cells (C20)) x 0.9 (efficiency of Fresh Air Blower Control Module (J126)).
• Terminals - A - and - B - (on the sunroof and sunroof frame) are used to transfer the electrical energy generated, and must always be clean and free of conventional lubricating grease.
• If necessary, terminals - A - and - B - can be lightly coated with contact grease (electrically conductive protective lubricant, available from suppliers of electronic equipment).
Solar Roof, Checking Function
- 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),
- Open the "center" instrument panel vents and close the remaining vents.
- Switch ignition off (A/C control head Climatronic Control Module (J255) is dark).
- Close sunroof.
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 coding of A/C control head Climatronic Control Module (J255) (on a vehicle with solar roof). Refer to => [ A/C Control Head Climatronic Control Module, Coding ] A/C Control Head Climatronic Control Module, Coding.
- Remove glove box.
- Disconnect connector - A - from Fresh Air Blower Control Module (J126).
- Measure voltage between terminal - 6 - and terminal - 3 - at connector - A -.
• Specification: 8 - 12 V = (depending on intensity of the solar radiation)
- Connect a test lamp (12 V with maximum 5 W) between terminals - 6 - and - 3 - on connector - A -.
- The test lamp should glow or light up (depending on intensity of the solar radiation).
• If test lamp glows or lights up, solar roof function is OK. If Fresh Air Blower (V2) does not run, check Fresh Air Blower (V2) moves freely; if no malfunction can be detected, replace Fresh Air Blower Control Module (J126 ) with Fresh Air Blower (V2).
• If test lamp does not glow or light up, check wire connection to both terminals at sunroof cut-out. If no malfunction can be detected, check the solar panel.
• 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).