HVAC Air Flow Switching to Defrost When Accelerating on Dodge Ram Wagon B350

Problem Description and Possible Solution

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.

Problem Data
RepairPal Verified
Average mileage: (–)
5 model years affected: 1990, 1991, 1992, 1993, more1994
5 people reported this problem
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews