Problems with your Alero's air conditioning are fairly simple to diagnose, whether it be an issue with the magnetic clutch or a blown fuse. Before taking your vehicle to a mechanic for what could be an expensive check up and repair, there are a few basic troubleshooting steps you can run through on your own.
Check the fuse box at the left of the dash board in the 2000 Oldsmobile Alero for any blown fuses. Read the instructions on the inside cover of the fuse box on how to locate the fuse connected to the AC system. If the metal wire inside the fuse is damaged, replace it with another of the exact same amperage.
Turn on the electric fan and the AC with the engine running to see if the controls are damaged in any way. Replace the dials, if needed. If the fan does not turn, it could point to a blown fuse, or the fan itself may have burned out.
Check for any oily refrigerant residue on the AC hoses. Have the hoses replaced if you notice leakage.
Set the AC and electric fan up to the highest setting with the engine running. Look under the hood to see if the magnetic clutch attached to the AC compressor engages. If it does not engage, the system may be low on refrigerant. Have a mechanic replace the refrigerant for you. A compressor that is excessively noisy may need to be replaced. The magnetic clutch may need to be replaced if it is receiving voltage but still not engaging the compressor. If there are leaks around the compressor shaft seal, the seal should also be replaced.
Test the AC system for adequate pressure. Attach the AC compression gauge with the engine off. Remove the black caps on the low and high side service ports on the AC unit. Screw the blue hose to the low-side service port and the red hose to the high-side port. A normal reading should be between 50 and 80 PSI. If the reading is not within this range, have a qualified AC mechanic investigate further for you.
Start the engine and check under the hood for the two AC hoses near the firewall to see if they are warm. However, one should be noticeably cooler than the other. If it is not, the valve control may need to be replaced. Have a qualified mechanic do this for you. The firewall is the metal partition between the engine compartment and the passenger compartment and extends from below the windscreen to beneath the engine.
