My 2000 Z24 cavalier makes just one solid click when I try to start it. Lights and power locks, steering, etc still work. Whats wrong?

It sounds like the starter motor seized or there's not enough juice to turn it over. Try removing the battery cables and cleaning the terminals. While the battery is disconnected, the electronics should reset.

Unfortunately that didn't work. Just tried it now. I also tried switching the a/c and ignition starter relays but it's still not turning over. Actually.. it's not even turning.

tap the starter with a hammer while trying to start.. 2ppl needed , if starts replace starter goood luck

If you have a starter the is just clicking you may still have a battery problem or connection problem. Have you check the battery voltage? Have you check the connection at the starter? And have you tried to turn thr engine with over by hand? This can be done with a socket and ratcheton the front of the motor at the crankshaft. Do you have a after markey alarm?

I had the same thing happen to a 2000 cav and I have cleaned cables and cable connections altenator shows it puts out 15 to 16 volts bkower on heater a/c isnt working and battery was taken in and a load test done checked good checked fuses in hood compartment but finding nothing wrong started car and heard sizzle under car one thing the starter does have a fuseable link that might be bad u might check that... but i am wondering if the altenator has a regulatopr or if the car has a computer to assist fuel