I have a 98 Saturn SL1 that blows no air at all, the engines fan is blowing, and it looks like the serpentine belt on the compressor is running too, and when you put the car on max cold the rpm's fluctuate. I think its just a fuse, but i'm not sure..any advice?

The cooling fan motor is likely drawing to much current because it is worn out.

Multiple possible problems, low freon, imprope install of serpentine belt, or more likely suction hose collapse due to faulty part design. If freon low pressure between 45~55 pounds pressure and serpentine belt properly routed around idler pully between compressor and alternator, then suspect suction line collapse which literally starves the compressor at idle and constricts the compressor at all speeds.

The fix, is to toss your existing suction hose and buy one of these custom modified hoses: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=181880844799


Look on eBay for KIA OEM suction hose pics and visually compare, this revision totally eliminates kinking and collapse.

What engine does your 2500 HD have? Is it a 6.6 diesel, a 6.0 gas, or an 8.1 gas engine? If it's a gas engine, the A/C compressor belt may have snapped (common). The gas engines used a separate, smaller belt to drive the compressor, while the larger serpentine belt runs the rest of the accessories. Diesel engines only have one belt that runs all accessories, including the A/C compressor.

Is ac compressor even coming on? Did it work before the water pump was replaced? Do the radiator fan(s) come on when ac is turned on?

check the vent flap by the blower to see that it is moving, you may have to remove the blower to get to it, if the flap is moving then check the condeser to see if it needs to be cleaned. For this you will need to remove the blower as it is on the other side of the blower. just use a shop vac to **** the dirt out of the grid, you may wash it out with water if you would like, however it may cause overspary to blow into your car.

If you didn't take the air compressor off the old engine then you probably have a bad compressor on the new motor. If you did then you may not have installed it or wired it correctly.

With the car in idle, turn the AC on and off and watch the rpms, they should fluctuate slightly when you turn it on and off, if they don't change at all then the compressor probably isn't wired to the controls.

The reason for the fluctuating RPM is that when the compressor kicks on it creates a load on the engine, which causes the rpms to temporarily dip down, the engine will then feed more gas to recover the original RPM.

hope you can see it

Standing on the passenger side of the car with the hood open looking down into the engine bay you will see the serpentine belt. If you have air conditioning, look directly below the air compressor pulley, the next one down is the water pump. Another easy way to find it is to find the lower radiator hose (again on the passenger side of the engine) and follow it to the engine block, the pulley where the hose meets the block is the water pump (not the pulley, but what the pulley spins is the pump).

my 2000 saturn sl blows cold air with the heater on. I changed the thermostat,and checked out my heater core.Still blows cold air.

If it happened all of a sudden, check the fan belt, and the A/C fuse. These are the most likely culprits. If the fuse is blown, the clutch on the A/C compressor may have gone bad, and should be looked at.