I have a 1997 dodge neon. The bottom pulley on the compressor is locked, but the top one turns fine. Which belt and pulley runs my air and which one runs the engine fan??

The likely cause is a bad compressor clutch, but there are other possible causes. The first thing to do is to observe the compressor with the engine running. The clutch is inside the pulley. When the a/c is off, the pulley turns on thr belt, but the clutch does not turn. When the a/c is turned on, the clutch should lock on the pulley and turn with it. Run this test and post the result here.

engine running do you see compressor turning let me no pierre

here you go.

the belt breaks due to bearing wear in one of the pulleys... check each pulley for wear by hand, I imagine you heard squealing noise...

The alternator belt on the 1999 Dodge Caravan also controls the air conditioner compressor, the water pump and the power steering pump. The belt is called a serpentine belt, and it is designed to fit around all of the accessory pulleys at the same time. As the belt travels around each accessory pulley, it enables the accessory to operate. Once the belt is damaged, cracked or frayed, you should change it before it breaks. If that happens, each of the accessories will stop working.

Open the hood and prop it up so that it does not fall. Engage the parking brake.

Inspect the top surface of the fan shroud for the serpentine belt routing diagram. Follow the routing instructions on the diagram to install the new belt.

Locate the serpentine belt self-adjusting tensioner on the front of the engine. The tensioner is directly below the alternator. Use the bolt that connects the tensioner pulley to the tensioner arm to rotate the tensioner.

Turn the tensioner device counterclockwise to move the tensioner. This will relieve the tension from the belt. Once the belt has enough slack in it, slide the belt out from under the tensioner pulley.

Lift the belt off each accessory pulley. Slide the belt around the fan blades and out of the engine area.

Lay the old belt next to the new belt to ensure that the new belt is the correct width and length. Slide the belt around the fan blades and around the crankshaft pulley on the bottom of the engine.

Follow the belt routing diagram to position the belt around the air conditioner compressor pulley, the power steering pump pulley, the water pump pulley and the idler pulley. Once the belt is routed inside each accessory pulley, inspect the belt to make sure that it is securely inside the pulleys.

Crank the 1999 Dodge Caravan for 10 to 15 seconds to completely seat the belt ribs in the grooves on each accessory pulley. Shut the engine off and close the hood.

If the belt routing diagram for the 1999 Dodge Caravan is missing, use a pen and a notepad to draw the exact routing of the old belt and use it when installing the new belt.

Sounds like your A/C compressor seized. Locate the compressor in the engine bay. Usually a large round aluminium grey component driven by a belt of the engine. These operate on an electro-magnetic clutch. Passing current through it will engage the clutch and connect the compressor drive with the pulley.
Start the engine, the front part of the compressor(drive) will be stationary(Even though the belt running over it will be moving on its pulley). Switch on the A/C. That same front part should now be moving, along with the pulley. If not turn off the engine. Try to rotate the compressor drive by hand. Not the pulley itself. If it is difficult to turn or does not turn at all, you have a compressor problem. A/C is not really user serviceable so have it checked out.

You could have a bad or worn serpintine belt. When you replace it make sure all the pulleys are rotating freelyi.e. air compressor, alternator, tensioner idler & power steering pullies to make sure all of their bearings are running freely. Good luck!

the defrosters run with the ac compressor running whenever its 49 degrees and higher. it does that to get rid of humidity faster. the pulley works off the ac clutch behind the pulley so you have a locked up clutch. find a belt to fit by bypassing the ac compressor will do if you like

1997 Plymouth Neon, have replaced radiator, radiation cap, thermostate and hoses, still run hot. Fans do not seem to come on, where is the temperature sensor on this vehicle?

it sounds like it was just the electric fan turning on, they can and will turn on even if car is turned off.