Heater/air conditioner. When I go over a bum then it will all work fine, and then the heater or air conditioner will stop working. When it does work, it works just fine it blows heat for the heater and cold air for the air conditioner. When they changed my spark plugs it worked again for a month and then it stopped. I replaced the whole panel inside the car. It's not the blower. It seems like it's electrical. Is there anyway you could tell me where my heater is located under the hood? And if it could electrical like something is loose. Or where can I get a free diagram if what's under my hood ?