The AC/heater (HVAC) system may unexpectedly switch to the defrost mode when accelerating. This system is operated by engine vacuum and should be inspected for any vacuum leaks if this problem develops. There is also a revised vacuum check valve available to address this concern.
HVAC Air Flow Switching to Defrost When Accelerating on Dodge Ram Wagon B250
Average mileage: 160,000 (160,000–160,000)
6 people reported this problem
1992 Dodge Ram Wagon B250 160,000 mi, Visitor
over 50% of the time when accelerating