When Audi engineers were designing the 5000 sedan for the 1984 model year, they decided to upgrade the climate control system at the same time. The pre-1984 system was based on a General Motors design and had been a source of problems. Audi decided to do away with the vacuum- and cable-operated dash controls used on previous models in favor of a fully electronic central control head. Along with this improvement came a fully automatic system that regulated the heat and air conditioning to control cabin temperature… or so they planned. As with many new designs, the climate control system was plagued with a fresh set of problems.