* Blower Motor Resistor: This component controls the fan speeds. A faulty resistor can cause the fan to not work at all or only operate on high speed (if at all). This is a common culprit.
* Blower Motor: The motor itself could be failing. It might be seized, worn out, or have a burned-out winding.
* AC Clutch Relay: This relay engages the compressor. If it's bad, the compressor won't turn on, even if the AC is switched on.
* Low Refrigerant: This is a possibility. A low refrigerant level will prevent the system from cooling effectively. You might not feel *any* cold air, or very weak cold air.
* Bad Blower Motor Switch: The switch itself could be faulty, preventing power from reaching the motor.
* Wiring Issues: A break or short in the wiring to the blower motor or other components is always possible.
* Compressor: While less likely given that you're mentioning no air at all (as opposed to warm air), a faulty compressor could also contribute.
Troubleshooting Steps:
1. Check the blower motor itself: With the ignition on, try listening carefully near the blower motor (usually located behind the glove box). Can you hear any noise (whining, clicking, grinding) when you turn the fan on? A completely silent motor strongly suggests a problem with it.
2. Check the blower motor resistor: This is often relatively easy to access and test (you'll need a multimeter). Look up a diagram or video specific to your 2004 Chevy Tahoe to locate it.
3. Check the AC clutch relay: Locate the relay and check if it's clicking when you turn on the AC. A simple swap with a known-good relay (same type/amp rating) can confirm if this is the issue.
4. Check the refrigerant level: This requires special equipment. A mechanic can do this easily. If it's low, there might be a leak somewhere in the system.
5. Check fuses again, but be thorough: There might be more than one fuse related to the AC system. Consult your owner's manual.
Recommendation: If you're not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic. They have the tools and expertise to diagnose the problem accurately and efficiently. The cost of a misdiagnosis and potentially damaging other components would likely exceed the cost of professional repair.
