Troubleshooting the AC Light Flashing on a Toyota

Common Reasons for AC Light Flashing on Toyota Cars

Toyota AC systems are designed to operate at maximum efficiency. To ensure the compressor is getting all the power it needs from the belt, the HVAC controller compares the engine RPM to the AC clutch RPM. If the values don’t match, the AC controller flashes the AC light. If you have a flashing AC light on a Toyota vehicle, you’ve got a slipping AC clutch or a slipping AC belt.

A bad AC relay is the most common cause of a flashing AC light on a Toyota

Toyota has identified a problem with its AC compressor

Locate a comparable relay and swap it with the AC clutch relay

clutch relays. Over time, the contacts in the relay become pitted and build up electrical resistance, which reduces current flow to the AC compressor clutch coil. That reduces the magnetic field, which in turn causes the AC compressor clutch to slip.

Check the part number of your AC compressor clutch relay. If the part number on the side of the old relay is 90987-02022, replace it with an updated relay, part 90987-02028. Then, operate the AC and see if the Toyota flashing AC light goes out.

If the updated relay doesn’t fix the problem and you’re sure the belt and tensioner are good, then the problem is with the AC compressor clutch.

If the relay is good, check for a slipping AC belt

Your first step in diagnosing a flashing AC light should be to check AC compressor belt tension and belt condition. If the AC compressor belt in your vehicle is tensioned by an automatic belt tensioner, follow the testing steps in this post. If the automatic tensioner is worn, replace it.

Check the serpentine belt for wear and slipping

Next, check the condition of the belt. NOTE: Newer belts are made from EPDM rubber. EPDM rubber does NOT crack like older neoprene belts. YOU CANNOT CHECK THE CONDITION OF AN EPDM BELT WITH A VISUAL INSPECTION. You must use a wear gauge. Measure the wear on an EPDM using this method. If the belt is worn, replace it.

©, 2019 Rick Muscoplat