Your first steps with a broken AC
Report the broken AC to your landlord in writing, keep copies, and document the conditions — including indoor temperatures — especially if AC was included in your lease or the heat is becoming dangerous.
A written report records when the landlord was notified. Note whether AC came with the unit, since that often decides whether the landlord must fix it, and keep the lease or listing that mentioned it. Photograph a thermometer showing the indoor temperature, and track how the heat is affecting your household, particularly anyone with medical needs.
If the AC is leaking, growing mold, or unsafe, mention that too, because those are habitability issues on their own. Take steps to stay safe in the heat while you wait. If your landlord provided AC and will not repair it, or dangerous heat is making your home unsafe, a free, confidential review can help you understand your options.
This is general information about California tenant rights, not legal advice. Every situation is different.