What causes air vents to stay in defrost position?
What causes air vents to stay in defrost position? If you have an older car then the defroster system is controlled by using vacuum supplied by the engine. Lift the hood and inspect the vacuum hose or tube that leads from the intake manifold to the passenger's side firewall. The image below shows a typical line break which causes the vents to stay in the defrost position. Why does my Chevy Venture take so long to heat? It affects Chevrolet Venture and Pontiac Montana vans also. In the winter, the van would take forever to heat up and when it...