AC fan working intermittently

usually relays are with the fuse box, under the bonnet

If you can't shift out of park with the key on, the problem is usually the brake light switch or the solenoid that locks the shifter.

if the fan slowly comes up to speed check the connections on the resister they over heat and melt then check the fan motor itself

relay located in the fuse box located under the hood, fuse/relay box is generally on L side of engine compartment.......fan relay should be marked under the cover...testing....try a new relay....they are cheap.
yet use a chrystler part!

Need to replace the blower resistor

this problem is caused by the blower motor speed control resistor being defective, it is located next to the blower motor.

thats normal its on temp switch

There is a fuse, but the heater motor (A/C) usually also runs some other things, but it is cheap to change the fuse and see what happens. More likely is the fan speed resistor pack. It isn't the easiest thing to find, but it is usually located in the air duct someplace under the dash. Does it do the same thing on all speeds, or just on one speed? If it does it on all of the speeds, then its more likely the fuse or the motor. If it only does it on one of the fan speeds or 2 out of 4 speeds, then the resistor pack is more likely.

If you are going to replace the engine then I would go and get a Chilton's Manual and do it by the book. This will save time and money.

replace the blower motor