My car produces very little heat. What should I do or what things should I look for to get more heat? is it a plugged heater core? or the vacuum switching valve?
First thing - is the engine up to full operating temperature? It could be low flow through the heater core due to crud. It could be that the cool air is bypassing the heater core if the temperature control door isn't full closed.
Your thermostat could also have failed and stuck open producing the same results.
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