Toyota Repair: 1992 Toyota Corolla engine cooling fan, toyota corolla, sensor switch

Question
As soon as I turn the key on my 1992 Toyota Corolla, the engine cooling fan turns on, why is that. Also they say that my a/c needs re-charged, I have the R-12.

Answer
The cooling fan turns on because there is either an open circuit in the wiring or the fan control switch, or the switch is disconnected. The temp sensor/switch is located on the thermostat housing, make sure the electrical connector is on tight, if it is the switch could be the problem so I would try a new one, if the new switch doesn't help there is an open circuit in the wiring between the switch and the relays.