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Q: Heater / A/C are not working properly. They are weak and the highest and lowest settings do not work at all. Any ideas what it could be?

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When I bought the car 3 years ago the level 1 heat/AC did not work, as long as I have had the car it has never worked. Approximately a year ago I had the water pump and timing replace. A couple of days ago I started my car and had absolutely no heat, the car would not blow any air out at all. I replace the fuse (hoping for a cheap and easy fix). After replacing the fuse the second and third level of air now work but blow out significantly weaker than in the past. The first level still does not work (and o don't honestly care about that) nor does the forth/highest level (blows absolutely nothing as if i turned the air completely off. I have tried resetting fuses heat and a/c, coolant is full but a bit cloudy. I was thinking maybe it is the blower resistor but if that were it it should work on high and not the other setting I thought.. I am hoping for another opinion, I would like to fix the problem withought guessing and fixing 1200 things. Any ideas what it could be? Thank you!!!!

My car has 170000 miles.
My car has an automatic transmission.

A: Hi there. Check the power from the switch ...

Hi there. Check the power from the switch on each setting and to the blower. See what the voltage is at each setting. If the voltage is low or not showing, then the switch is not working and needs replaced. The switch has a resister built in it to make the blower have different voltage outputs which makes the blower have multiple speeds. However, the first setting and the last setting could have a burned element inside making only the second and third setting work. Once you have the blower working properly, if there is no heat, then check the heater control valve in the engine compartment for if the vacuum line has came off or if the valve is not working. When the engine is at operating temperature, check the temperature of the coolant hoses to the valve and after the valve. If the hoses are the same temperature and the valve is shut, then the valve is on or not working. If the temperatures are different, then the valve is off or not working. If you need further assistance with your heater and a/c not working, then seek out a professional, such as one from Your Mechanic, to help you.

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