Turning on defroster kills engine

[Bryan]

:stick: I have a 2006 Galant V6, battery died, had it checked and was told needed a new alternator. Put on new alternator. Then the engine started dying each time I turn on the defroster unless I keep it revved up. Any ideas what would cause that. It never did it before. Thanks.

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[Muharem]

Seems to me like something is wrong with that alternator or battery. Maybe the defroster is sucking too much power from it and then alternator tries to produce that power which ends up in bigger drag on the engine. Do you experience any problems when you turn all your lights on, radio, and stuff like that? Does that cause your engine to die? Have you checked your battery?

[zero]

I would check the alternator and battery again.

[Bryan]

Will be having a full system diagnostics performed tomorrow. Thanks for your help.

[Muharem]

Keep us updated and good luck. 🙂

[Bryan]

Firestone says that it is not the alternator or battery. It’s the AC compressor, dryer and condenser that is bad. I guess it could be but it still blows cold, it just strains the engine so you have to keep more rpms to run it. The thing that gets me is it never did it prior to replacing the battery. Thanks again for you concern and help.

[Jim Davis]

Before you let anyone take a bunch of your money repairing the AC, even if you have to take that new alt off and have it tested, have it tested again, somewhere else. I am betting it is dragging when a load, such as the ac, is put on it.

[Timothy Salomon]

If it is the AC compressor, it should also drop the RPM on max AC. Many older cars used a system to retard the ignition timing to increase the rpms to keep the engine from dying. Do your rpms increase when you turn the AC on? Does the car idle a little slower than it should normally? Probably around 750 normally and 900 rpm with the AC on?

[Author]

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