Electric Fan

where do i have to hook into to put an on/off switch for the electric fan in the dash?

The fan will cycle on if you disconnect the T stat coolant temp sensor while the engine is running. Maybe you could wire a switch in parallel with the sensor. Or if you don't mind the check engine light being on just leave the sensor disconnected, or remove the sensor and plug the hole then secure removed sensor to nearby object. that would allow the fan to run all the time and the light wouldn't be on. Just my two cents worth.