Solar Sunroof, Electrical Testing
Solar Sunroof, Electrical Testing
NOTE:
- 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 flap 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 flaps 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 the 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 Climatronic Control Module J255), the Fresh Air Blower Control Module J126 checks the voltage at the input from 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/sq.m is approx. 12 W:
500 W/sq.m (solar radiation) x 0.21 sq.m (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 Sunroof, Testing Function
- Place vehicle in direct sunlight.
NOTE: If weather conditions are unfavorable, the solar sunroof can be illuminated using two commercially available 1000 W halogen lamps. These must be set up at a distance of at least 500 mm (19.7 in) from the surface of the solar sunroof. So that the Solar Cells C20 can supply sufficient electrical energy to drive the Fresh Air Blower V2, make sure that all sunroof Solar Cells C20 are illuminated completely and evenly.
- 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.
Air should be flowing from the instrument panel air vents (if necessary, check by moistening hand and holding in front of vent).
If no air flow can be detected:
- Check coding of A/C control head Climatronic Control Module J255 (for "vehicle with solar roof").
- Remove glove compartment.
- Disconnect electrical connection - A - from Fresh Air Blower Control Module J126.
- Measure voltage between terminal - 6 - and terminal - 3 - on connector - A -.
- Specified value: 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).
NOTE:
- If test lamp glows or lights up, solar roof function is OK. If Fresh Air Blower V2 does not run, check that 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 ( Fresh Air Blower V2 turns, but air flow is difficult to detect).