Car Problem Reports

Dodge Ram Van 1500 HVAC Air Flow Switching to Defrost When Accelerating

 
Dodge Ram Van 1500 Problem
79 Reports
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Model Years Affected: 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003

Average Mileage: 129,638 mi (50,000 mi - 272,000 mi)

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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.

  • Visitor, , 200,000 mi

    A/C blows normal until you accelerate then it moves to the defrost vents then the feet vents. when I lift off the gas it imediatly returns to normal.

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  • Visitor, , 135,765 mi

    my problem is that it stays on defrost wont change to heat or vents. does antbody have a solution

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  •  Rookie

    We travel on the highway as we increase speed the ac/heater switches over to defrost ....we release the gas pedal it switches back to normal any solutions.

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  • Visitor, , 174,000 mi

    heater/ac only works on defrost

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  • Visitor, , 170,000 mi

    ac and heat only comes out on defrost.

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  • Visitor, , 135,000 mi

    a/c switches to defrost on acceleration or moderate incline

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  • Visitor, , 125,000 mi

    A/C blows normal until you accelerate then it moves to the defrost vents then the feet vents. when I lift off the gas it immediately returns to the floor.

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  •  Rookie

    I have a 1996 dodge ram 1500 with 3.9. when I accelerate the ac/heater switches from vent to defrost, I dont know how to fix or check for problems

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  •  Rookie

    AC/heater awitches to defrost when acceralating

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  • Visitor, , 160,000 mi

    I have the same problem on my 97 3.9L B1500 I installed two check valves this did the trick

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