What turns the fan on a 1995 Chevy lumina fan

All electric..thermostatic switches. When the coolant gets too hot a switch is tripped that fires up the fans. There is a mechanical valve too, it directs hot coolant away from engine.

it seems to be on the bottom left front of front of the intake right below the thermostat. Good luck for you!
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auto key programmer x-100

This year doen't use a separate sensor for the cooling fans, it uses the ECT (engine coolant temp sensor) sensor that monitors engine temperature for the fuel control system, the computer turns the fans (via a relay) on when the engine reaches about 225-230 Degrees F

It sounds like a bad fuel pump.

How did you determine that the sensor failed. Did the check engine light come on? When you say that the fan won't turn, do you mean that it won't turn on and run or that you can't physically turn it by hand. To determine this, disconnect the electrical connector to the fan and try to turn it by hand. It should turn easily. If it doesn't then it must be replaced. If it does then reconnect the electrical connector to the fan and try to operate it by disconnecting the temperature sensor lead and placing a jumper wire between the terminals of the harness. turn the AC control to AC/MAX and turn the ignition key to on. If the fan runs then the problem is the sensor. If it doesn't then check the fan control relay and any related fuses. WARNING : Use extreme caution when testing the fan circuit. Never attempt to turn the fan with the electrical connector in place. The fan can operate at any time even if the engine is off.

The fan switch will be near the thermostat housing,you'll see one or more sensors there,this picture will help you get the correct one.

very common for the turn signal switch to fail on these vehicles... its located in the column , have to remove the steering wheel...

where is the signal light flasher located on a 1996 chevy lumina

ignition switch under coils

lift the rug at edge of the floor right above the bumper there is a big nut turn counter clockwise