Window lifts and relays
| Window lifts and relays |
The window lifts are operated from five switches located in the switch panel on the centre console. The switches are connected to the STC control module, which activates the corresponding window lift relay to operate the electric motor for that window lift. The window lifts are driven by DC motors, which change their direction of rotation by reversing the polarity of the motor terminals so that the window can be raised and lowered.
Each window lift has its own relay, which supplies the corresponding window lift motor. The relays are mounted in two relay holders behind the right and left side trim.
The switch-over contacts of the relay, which control the direction of rotation of the window lift motor, are voltage fed on pin 1 on the front right/left relay from pin 14 (22a) and on the rear right/left relay from fuse 7 (22a). Power ground is from pin 5 to grounding point G36 for the left front/rear relays and grounding point G24 for the right front/rear relays. The integrated circuit is activated with +54 voltage to pin 2 on all the relays from fuse 21 (22a) and is signal grounded via pin 6 on all the relays to grounding point G36. VR bus communication takes place on pin 8.
The STC control module controls the relays with the following messages on the VR bus:
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Front left window DOWN, unit ON/OFF.
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Front left window UP, unit ON/OFF.
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Front right window DOWN, unit ON/OFF.
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Front right window UP, unit ON/OFF.
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Rear left window DOWN, unit ON/OFF.
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Rear left window UP, unit ON/OFF.
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Rear right window DOWN, unit ON/OFF.
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Rear right window UP, unit ON/OFF.
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When being opened, each respective window lift is supplied from the relay pin 4 and grounded via pin 3. When closing, it is supplied from the relay pin 3 and grounded via pin 4.
All the window lift relays and the relay for the fifth bow latch motor are identical. Therefore, the relays are programmed for their position, e.g. “Front Left window lift”. When replacing a relay, it is therefore necessary to program it with the diagnostic tool.
When the soft top is being raised, the control module lowers the windows approx. 15 centimetres to prevent the soft top from jamming on any of the windows.
It is only possible to operate the window lifts DOWN with any of the five switches while the soft top is being raised.
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