My heater keeps switching from heat to defrost to dash vents.What is going on with my vacume system?

 

99 out of a 100 times this issue is because either the vacuum check valve is no good or there is a vacuum leak in the vacuum line that feeds the HVAC controls.

 

Thanks for getting back to me so soon Alloro.I'm also having problems with my blower resistors put 2 in already.What go you think MOTOR or what?

 

How long between changing the resistors, and did you use aftermarket ones, or OEM ones from the dealer?

 

One year, 1st resistor aftermarket , 2nd one dealer, only lasted one month.

 

How is the condition of the connector for the resistor? There is a replacement pigtail available with larger wires. It's supposed to take care of an overheating problem with the connector.

If the connector is in good shape, then you might be looking at replacing the blower motor. As it wears it draws more and more amps. This extra draw could burning up the resistors.