Tony:
I'm not too sure about the Celica's, but i know the corolla's have two cooling fans, one on the a/c side and one on the engine coolant side. The idea of this, is one primarily runs it's own 'radiator', but also helps to cool the other. The a/c cooling fan will come on when you turn the a/c on, because the more air flowing over that radiator, the better. Both fans will go on when hot, and should only die when turned to the accessory position as the engine is at operating temp and will overheat if they go off.
The fans will stay on afterwards (even in the Lock position), however, if the car has overheated, to help cool the engine back to operating temprature,then will switch off once there (I found this out when my engine cooked itself)
To get to the main point, the a/c switch really has nothing to do with the fan relay directly, it just puts more load on the engine and increases the idle thru the vacum valve, which in turn heats it up quicker. This then triggers the Coolant Temp sensor to turn the main cooling fan on, thus, both fans are then running.
Hope this answers your question at least a little.. If all is normal, including your thermostat and water pump, you shouldn't overheat again, no.
Spud.
I'm not too sure about the Celica's, but i know the corolla's have two cooling fans, one on the a/c side and one on the engine coolant side. The idea of this, is one primarily runs it's own 'radiator', but also helps to cool the other. The a/c cooling fan will come on when you turn the a/c on, because the more air flowing over that radiator, the better. Both fans will go on when hot, and should only die when turned to the accessory position as the engine is at operating temp and will overheat if they go off.
The fans will stay on afterwards (even in the Lock position), however, if the car has overheated, to help cool the engine back to operating temprature,then will switch off once there (I found this out when my engine cooked itself)
To get to the main point, the a/c switch really has nothing to do with the fan relay directly, it just puts more load on the engine and increases the idle thru the vacum valve, which in turn heats it up quicker. This then triggers the Coolant Temp sensor to turn the main cooling fan on, thus, both fans are then running.
Hope this answers your question at least a little.. If all is normal, including your thermostat and water pump, you shouldn't overheat again, no.
Spud.