[jhv48]

Two things, check the amp/volt gauge on your dash with the car running. If the amp gauge is slightly to the left of the center line, you are running off of the battery only and your alternator is either not functioning OR the wire connecting it to the system is broken/disconnected. If the volt meter doesn't show around 13 volts when running, you've got an alternator/regulator problem. Do your dash gauges fail to work with the engine running? That's because there isn't enough battery power to run your engine and any accessories.

Does your amp meter jump in the negative range about -25amps when the fan comes on? If so, alternator isn't connected or is faulty.

If you can start the car with the jumper battery, then your wires from the battery to the rest of the car are fine.

My guess is that you are running only off of the battery and when the fan kicks on, it uses so much power that there isn't much left to power the engine.

Trace the wire leading to/from the alternator. You will find a break or loose wire. Your battery may be shot too, due to the continued draining. Take it to an auto parts store and have them test it and fully charge it for you. O'reilly does this for free.