1. You may need to grease the sliding roof rails, special (expensive) stuff, and/or clean out the cable tube.
2. Your CCU may have failed, pull it and inspect for cold solders, this is the usual suspect.
3. Can't help.
4. There is an OVP relay with a fuse on it, inspect for replacement, not sure where it is.
5. Normal, the usual suspect there is the amplifier located on the steering column.
6. I don't think so, but check all fuses by completely removing them and inspect the ends.
BTW, your SD looks familiar! lol

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83 SD

84 CD