These vehicles have two separate temperature sensors. There is one located in the thermostat housing which tells the ECM when to turn the fans on and off. There is one located in the rear cylinder head on the driver's side that reports the engines temperature to the gauge inside the car. If the sensors are okay check the cooling fan relay, located in the underhood fuse panel. This can be diagnosed using a scanner and viewing the cooling fan status.
Radiator plugged or restricted? May need to be boiled out Cooling fan not working? water pump not circulating coolant?
1991 Corsica its under the trottle body
Green coolant (prestone, etc)
Air conditioner is malfunctioning possible needs to be recharged or the compressor replaced
Place something to catch the engine coolant beneath your 1990 Chevy Corsica radiator. Remove the radiator drain plug with a 9/16 ratchet. The engine coolant will drain out.
Hand tight
WHAT DOES THE DIAGRAM SHOW?
The evaporator for a Chevy Corsica can not be unclogged. When it gets blocked, the evaporator can only be replaced.
Leak in heater core
If the coolant fan does not operate on a Chevy Corsica, it is likely that a fuse is out. There could also be a mechanical defect in the fan or wiring.
there are 4 relays on the passenger side firewall which one is the cooling fan relay
Just went thru this, was the radiator. Best way is to have your cooling system pressure tested. We replaced the radiator, upper hose, lower hose and a bad thermostat. Later our water pump failed, and then the heater core. I have replaced the whole cooling system, and would be happy to help you with any future questions. T HEMPLE