06 Taco intermittent A/C issues. For god sakes help!!

I have been dealing with this problem for literally years now, my A/C will shut off. The blower will continue to function but it blows "warm" air and the A/C light will blink randomly. The blower never shuts off only the compressor, this happens EVERY day. It is very sporadic but also very frequent happening multiple times per day. I just continually hit the A/C button when it starts flashing to turn it off then press it again to turn it on. Usually after 2-10 times (different every time) of doing this it will stay on for a while. There is no squealing or noises of any kind when the compressor shuts off or engages. When the A/C is working it cycles properly and I have zero issues. I took the truck in to have the system vacuumed and coolant replaced last year.

The ambient temp in Kansas today is 75 degrees with 66% humidity.

The A/C gauges read as follows:
- With vehicle off-
-low side 5.5kg 80 psi / high side 5.5kg 80 psi
- I test the system with engine warm, all doors open, blower on HI, A/C on max, recirculate at 1500 RPM A/C was blowing 46 degrees F.
-low side 5.5kg 80 psi / High side cycled between 12kg 175psi and 15kg 220 psi.
Note: When I tested the system with the gauges the A/C did NOT turn off at all.
- After vehicle has sat for 10 min-
- low side 4.75 kg 68psi / high side 6.0kg 85 psi.

I have replaced the magnetic clutch relay, replaced the compressor pick up sensor , cleaned/replaced the cabin filter, put a new serpentine belt on.

Any and all help is much appreciated!

 

The A/C light flashing has nothing to do with system pressures.

The flashing A/C light is when the A/C amplifier does not detect a speed signal from the compressor lock sensor after commanding the MG CLT relay on.
Possible causes are:
Open or shorted wire(s) in the lock sensor circuit
Faulty lock sensor
Internal problem in the compressor
Open or shorted wire(s) to the MG CLT relay
Open in the wire from the MG CLT relay to the compressor
Failed compressor clutch
Belt slipping
Failed A/C amplifier

Since your problem is intermittent I'd kinda suspect a wire that is intermittently shorting to ground or going open circuit or a compressor clutch that is going open circuit when it gets hot.

You will really need to check things when the problem is occurring.

The MG CLT relay should have power on pins 2 and 5 when the ignition switch is on, the A/C amplifier grounds pin 1 to turn it on.
You can momentarily jump pins 3 and 5 of the relay to see if the clutch engages.
Also check the wiring between the lock sensor and A/C amplifier.
The sensor signal itself can only be effectively checked with an oscilloscope.

 

Thank you Dm93, I will check all of those things asap.