Ram Van B250

HVAC Air Flow Switching to Defrost When Accelerating on Dodge Ram Van B250

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: 145,646 (86,555–251,000)
5 model years affected: 1990, 1991, 1992, 1993, more1994
18 people reported this problem
Viewing 1 - 6 of 6 comments
When accelerating my a/c switches to heat at any setting on the a/c, also I have a acceleration problem no power when accelerating thinking catalyst converter
I wish someone would post how to fix it. It seems to be a wide complaint. Seems someone from Dodge or any good mechanic would post the cure.