The high pressure sensor is not open by default, it is closed by default, because, it don't check for to high pressure, it checks the high pressure side. They are used to check whether there is sufficient pressure on the high-pressure side. This is the case when there is enough refrigerant available. Too less refrigerant, then the switch is open due to the lack of pressure in the high pressure side to prevent the compressor from damage.

 

Thanks for the fast reply, N!

Right. That's what I said -- Hi Pressure is closed by default. But I understood excessive pressure opens the switch to protect the compressor vs sufficient pressure (on the high side) to close the circuit, which would mean it has to be open by default.

If HP is closed by default, how would it know if there is enough pressure on the high side?

Maybe I'm not getting it -- but at the end of the day, I'm looking for the correct findings for a working Hi Pressure sensor off the vehicle -- should there or shouldn't there be continuity?

Thanks again.

 

Sorry I write it wrong.. that's because English is not my native language..

The high pressure switch is normally open.....!!!

Because it checks if enough pressure is in the system. It close when enough pressure is on the high pressure side ...

 

Sorry I write it wrong.. that's because English is not my native language..

The high pressure switch is normally open.....!!!

Because it checks if enough pressure is in the system. It close when enough pressure is on the high pressure side ...

No worries, mate. Your English is better than my German, that's for sure.

This is where my previous assumptions had come from, FWIW. Starting at 8:54, he covers the HP switch:

Thanks for the assistance,
Jimbo

 

I researched again and it could be that the high pressure sensor is actually measuring excess pressure. But perhaps it is such that it is normally closed and opens when it measures pressure. If your age and the new one are obviously the same, I wouldn't worry about it.

What is the reason for swapping the sensors. Is your air conditioning not working? It is rarely the case that the sensors are the problem. Mostly is the not sufficient amount of refrigerant.

 

Yes, both old and new switches do NOT have continuity, so you are likely correct -- and I won't worry about it (now).
To answer your questions, based on the video and my old switch/sensor not having continuity, I thought that would be the problem and I read somewhere, it's a possible cause for compressor cycling off/on.
I was doing this while I awaited my gauges which I hooked up yesterday and pressures are low -- when the compressor is cycling, I get L: 22 and H: 140; when compressor is not running, L is 84 and H is 85; it seems I have a leak... my preliminary visual inspection hasn't yielded an obvious leak.
Measured at 77 degrees F (25 C) and 40% humidity
On a 2004 Escalade -- I don't think the AC has ever been serviced.