So here is my problem. I bought the car this winter and only drove it a couple miles a day. Once it started warming up outside and I dropped the top and went on a small road trip the engine really warmed up! I found out the fan wasn’t working. I have verified that the fan does “work”, (by hard wiring it to a toggle for now), there is 5 volt on the terminal at the temp unit by the thermostat, the temp unit under the exhaust manifold works still and when wired right (before my toggle switch) the fan would come on for the AC and heater but that was it. I am not sure where to go from here on tracing this down.
What I do know about the car is that the motor is a 350 crate with TBI and stock rebuilt auto trans. Both in great shape and I am dieing to keep them that way  any help on tracing this down would be greatly appreciated! Thanks guys!

 

The coolant temp sensor tells the computer what the temperature is and the computer turns on/off the fan according to that. I think there are 2 temp sensors, one to show engine temp to the gauge and one for the computer.

 

you have a coolant temp sensor and a fan switch both that work off of different circuits. the temp sensor just tells you how warm your engine is running. While the fan switch detects how warm it is and turns the fans on. The fan swtch that measures coolant temp determines when to switch the fans on. Sounds like you have a bad fan switch. they are fairly in expensive