Will the electric fan on a 1987 Jeep Cherokee 4.0 work if the thermostat is bad?
The temperature switch for the Secendary electric fan is on the radiator. The coolant needs to reach around 190 deg as it is exiting the radiator before the secondary fan will turn on. If the thermostat is stuck in the closed position the engine will overheat, No coolant flowing through the radiator, If it is stuck in the open position then the engine will take a long time to warm up. a stuck thermostat should have no effect on the electric fan working or not. The most common cause of the fan not working is the temperature switch not working.