Car Problem Reports

Dodge Dakota HVAC Air Flow Switching to Defrost When Accelerating

Dodge Dakota Problem
14 Reports
Me Too

Model Years Affected: 1990, 1991, 1992, 1993, 1994, 1999

Average Mileage: 182,666 mi (120,000 mi - 280,000 mi)


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, , 120,000 mi

    No solution yet. Switches to defrost vents under acceleration. Suspected vacuum issue.

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  • Same here,no vaccuum leaks and all the check valves under the hood check fine.

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  • air flow switches from bilevel to defrost when accelerating

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  • Visitor, , 148,000 mi

    Air flow in vehicle keeps cycling and flips some sort of gate in the heater duct in driving gear timing seems horrible...In park or nuetral it sounds decent but still using an incredible amount of gas.

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