AC compressor Not coming on - Pressure switch - low freon?

I have a 2007 Prius which was having difficulty with AC compressor working when vehicle was stopped or running at low speeds - now it does not come on at all.

I checked the pressure on both low and high side it is between 75 and 80 psi at 74 F air temp. I have not found in searching if this is too low to activate the low pressure sensor. I do know when the compressor is running that 40 psi is normal for low and high would be much higher so it seems that this should be enough to activate it.

I measured the dual switch 4 wire pressure sensor - the leads on the pressure sensor are red, green and two white with black stripes. I assume that measuring the sensor between red and one of the white/black would be one either the high or low pressure sensor and similarly green and one of the white/black would be the other sensor.

I measured between red and white/black opposite and it shows closed.
I measured between green and all other pins and it showed open.

Here are my questions.
1) Is the red - white/black pin associated with the low pressure or high pressure sensor?
2) Should 75 psi at 74 F air temp be sufficient to activate the low pressure switch?
3) Is there any fuse associated with the AC compressor which should be checked - if so where is it?
4) Any other suggestions on how to proceed in determining why the compressor is not coming on with the doors open full ac at lowest temperature setting?

Thanks in Advance
johnh...

 

Thanks for the reply.

I did not find any codes using a torque pro app.

Can you let me know how to "get the codes"?

johnh...