I have a 96 z28 its manual. Ive replaced all the main things (radiator, water pump, thermostat, fan "switch", hoses). We checked the fans by attaching them to the battery, but wont start up in my car. Today I started it and drove off right away, it was almost to red before I pulled over. My heater was blowing cold air, something clicked and started blowing hot air and my car went back down to the middle temperature. What could it be? I've heard different things, something about clutch fan?

 

I'm going to assume that you're talking about your engine cooling fans and not the fan for your HVAC. Have you checked the relay and fuse in the engine bay? Those may have bene damanged when the rest was replaced if they were not pulled or the battery was not disconnected.

 

yeah it's the fuse. I was havin the same problem I went through the whole cooling system. I got wired mine to the battery and they came on. I sent it to the shop yesterday and they jus called and said it was the fuse.

 

the radiator fan should not have anything to do with the heater not putting out hot air. if the heater is pushing cold air when the motor is hot it usually means your very low on coolant. first check the coolant level in the radiator. if its full then i would suspect the thermostat is sticking. heat from the heater is controled by a flap that runs the air threw the heater core for heat and does not for cold.