I have a 1994 chevy cavalier 2.2L engine. the engine fan does not turn on causing the car to over heat. What makes the fan turn on, is it a thermostat or a fuse?

O2 sensor. Doesn't come on all the time. Gives false signal at times. They carbon up and need to be sandblasted or replaced.

sometimes the fan can run for up to 5 minutes after engine shut off depending on coolant temp as long as the vehicle is not overheating and the fan turns off after a few minutes this is normal operation

test your fan motor.run b+ and ground to your motor and see if it runs.if it doesnt it is probably your coolant fan switch located on the cylinder head or the coolant fan relay.hope this helps.keep posted.

the ecu control all sistems but use ground then check the wires . when you step on the gas runs or when you makes a turn ....... then a loose wire is making false contac

The blower motor is located under the hood in the engine compartment on the rightside on the firewall, also check the blower resistor this goes bad often and it will also stop the fan from working, test the blower, hook it to power and a ground if it turns on then its the resistor. hope this helps.

check the coolanr fan see it works,if it doesn't works can cause your car over heat. -if fan doesn't works , check the fan relay.

make sure that first the anti freeze level is correct. Then check the temputer sensor-fan might be cutting out if sensor is miss reading.1. temp sensor 2. fan

if there is a leak then of course you will get overheating from the engine..Be very careful as this can cause permanent damage to the head gasket and it will cost a lot more to fix..First try to stop this leak before you proceed further.

Could be one of two things...
The switch that turns on your fan could be failing. wiggle it to see if that helps, otherwise you will need to have it tested with a meter, or test light.
Or, there is a resistor deal near the motor (under the dash on the passenger side close to the floor) Look to see if it looks burnt, as this is a common problem.

Get a new tensioner and replace new belt. Here is a diagram to help you. Contact me if you need more help, Good Luck http://www.2carpros.com/car_repair_information/tec_info/1994/chevrolet/cavalier/1994_chevrolet_cavalier_drive_belt_routing_diagram.htm