How can I resolve issues with the rear air conditioning in my 2021 Toyota Highlander?

Diagnostic Steps

1. 1Check the rear AC controls for any visible signs of damage or malfunction.
2. 2Ensure that the rear AC is turned on and set to the desired temperature.
3. 3Locate the high and low-pressure service ports on the AC system.
4. 4Connect the refrigerant gauge set to the low-pressure port.
5. 5Start the vehicle and turn on the rear AC to the maximum setting.
6. 6Check the gauge reading. Ideally, it should be between 25-45 psi.
7. 7If low, it may need refrigerant. Add refrigerant as needed.
8. 8Locate the rear blower motor (usually under the rear passenger area).
9. 9Disconnect the electrical connector from the blower motor.
10. 10Use a multimeter to check for voltage at the connector with the rear AC on.
11. 11If no voltage is present, check fuses and wiring.
12. 12If voltage is present but the motor is not working, replace the blower motor.
13. 13Locate the cabin air filter access panel (usually under the glove box or behind the dash).
14. 14Remove the access panel and take out the filter.
15. 15Inspect the filter for dirt and debris; replace if necessary.
16. 16Check the rear AC vents for obstructions.
17. 17Use a flashlight to inspect the ductwork for blockages.
18. 18Clear any debris or obstructions using a vacuum.
19. 19Add UV dye to the AC system (if refrigerant was low).
20. 20Run the AC for 15-20 minutes and check for leaks using a UV light.
21. 21Inspect all connections, hoses, and seals for signs of leaks.