The manual ventilation system (not climate control), on my Mk 2 October 2000 diesel, is stuck on max hot. I assume the relay switch is the problem, but none of my local Ford main dealers are able to identify which relay switch is responsible. They are all individually numbered, so they can be easily identified and replaced, but only if you know which one is responsible for which task, and apparently they are unable to find that information on their system!! The blower speed control and air distribution control are still working normally. I would be very grateful any suggestions or layout diagrams.