AC issue

I have a 2015 Tacoma TRD with 75K miles and the a/c works great and then all of a sudden will quit. The blower continues to run and there are no blinking lights, squeals or any thing out of the ordinary. I replaced the compressor sensor last year due to a blinking light issue and even then the ac would work sometimes. While driving the ac works fine as i mentioned above but will stop blowing cold air. I can turn the ac off or turn the thermostat up and wait a few seconds, generally 30 seconds or less, and then it will start to blow cold air again. I am a retired residential/commercial ac guy so i know a few things about auto ac. Probably just enough to be dangerous.
The pressures are normal and the condenser fan is clean. This is an intermittent issue as it may do this once or twice a day or it may be several days or a couple of weeks before it does it again. I have checked the clutch and there is no excessive clearance and very little rust. I have checked voltages when it is idling and all are in acceptable ranges. Obviously i have not done any troubleshooting while driving. This issue only occurs while the vehicle is moving. I have let it idle for over an hour and no problem.

 

Sounds like the A/C Amplifier is shutting down the A/C on purpose, if you had an issue on the clutch or Lock Sensor side you would get a flashing A/C light when it shuts off.

My primary suspects to check would be the Evaporator Thermister and the Dual Pressure Switch.

The Dual Pressure Switch should stay closed under normal conditions and only open if pressure on the liquid line drops below 28 psi or goes above 455 psi.

 

Thanks, the pressures are well within the ranges listed and air is super cold when operating I will try the evap sensor and see what i find there.

 

I guess I should have stated the pressures for you. 32 psi for the low side and 230 for the high side at 90 degree ambient

 

Pressures are perfect.

Intermittent issues are the worst to track down, like ai said I'd investigate the pressure switch and evaporator thermistor circuits first as those are probably the easiest to check.

The A/C Amplifier is behind the glovebox in the middle looking straight up.

 

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