Ahh... loose contacts in the connector. If I only had 10c for evry time I've fixed a loose-contact problem!

It'll be affecting the RGB and Sync lines.

Solutions:
1. Contact cleaner spray. Spray and hope :-)
2. OR Tighten the contact pin pressure with long nose pliers. A trick is to deform the pin slightly to make it apply better pressure
3. OR: replace any suspect / corroded pins with new ones. Available from BMW, cheap