Automotive Air Conditioning Information Forum

97 Camry ac light starts blinking while indoor blower set to any speed except max. Hook up gauges and it appears that once it hits 25 PSI it shuts off fans and clutch and starts blinking. On max blower speed it keeps low side above 25 psi. Compressor replaced last year. New clutch and fan relays also installed. Condenser fans are working fine.

Your Camry has a sensor located on the bottom of the compressor that compares the engine tachometer's signal to the RPM signal of the compressor. If they don't match, the light on the A/C button will flash.

A flashing A/C light might further indicate a worn and slipping drive belt, a defective relay, an overcharged or undercharged system, too much oil or the wrong type of oil in the system, a slipping magnetic clutch (weak coil or too wide of an air gap), a defective A/C amplifier, or the sensor itself could be bad or ungrounded.

First guess would be a low charge, especially since the low-side pressure drops below 25 PSI, and then the system shuts off.

Suggest recovering the refrigerant (or having it done) and comparing how much refrigerant comes out to the manufacturer's specification. If there's a substantial difference, then the system has a leak somewhere.

The specs that I have for your car are as follows: 28 ounces net weight of R-134a, and 8.0 fluid ounces of PAG-46. If you have an under-hood decal that lists specs different from the above, then the decal takes precedence.

If I remember correctly this car used to cycle on and off between 25 and 45 psi. It does not do it anymore, once it hits 25 PSI it shuts off ac system. I did try adding some extra refrigerant but it did not make any difference. High side goes above 200 psi and fans will start running really high speed until high pressure drops.

Nedzad1 wrote: Thu Aug 14, 2025 7:25 pm If I remember correctly this car used to cycle on and off between 25 and 45 psi. It does not do it anymore, once it hits 25 PSI it shuts off ac system. I did try adding some extra refrigerant but it did not make any difference.

It depends on the heat load. At moderate ambient and cabin temperatures, the compressor should cycle. At higher temperatures, the compressor might not cycle at all. This behavior "assumes" that the system has a correct refrigerant charge.

Your car also has a transducer on the evaporator core that keeps it from getting too cold, freezing the condensate, and blocking airflow. Because the transducer cycles the compressor at ~25 PSI, it sounds like it's doing its job, shutting off the compressor before the evaporator can ice-up. However, the low-side pressure dropping that low also suggests a low refrigerant charge.

One of the first things to look at is to check the charge amount by recovering the refrigerant, weighing it, and comparing the result to the manufacturer's specifications. Any competent shop having a Recover/Recycle/Recharge (RRR) machine for R-134a can do that for you for a nominal fee. Since your car holds a relatively small amount of refrigerant, that amount needs to be exact for the system to operate properly.

Nedzad1 wrote: Thu Aug 14, 2025 7:25 pm High side goes above 200 psi and fans will start running really high speed until high pressure drops.

The fans appear to be working normally, so that's good.