A/C Pressure switches

[Studio54]

Just to confirm there is a high pressure switch, low pressure and a cycling switch.

Mine is a 98, high pressure switch is on the back of the compressor correct?

Low is on condenser and where is the cycling switch?

Can i take off the high pressure switch to replace it WONT leak my system? It has a shrader valve correct?

My compressor runs constantly and the wiring is all correct so now I'm going towards the pressure switches as I've heard that a faulty high pressure switch would cause it to ground and constantly run. (which is what mine is doing and freezes)

Any/all help is appreciated.

 

[1997chevydriver]

I have never heard of the hp switch causing the lines to freeze. Unplug your low pressure switch and see what happens.

Your compressor shouldn't turn on at all while the low pressure switch is not connected.

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[SAATR]

The low pressure switch cuts the compressor off when the low side pressure drops below a preset limit; the high pressure switch does the same when the high side pressure exceeds a preset limit. The compressor running all the time is not necessarily a sign of a failure in the system, as when and if the compressor cuts off is largely a function of the systems state of health, charge level, and ambient temperature. In certain circumstances the compressor won't cycle, because it will not push the system pressure past the high side limit or below the low side limit. Freezing lines on the low side generally means that the low side pressure is TOO low, and could be a sign of a faulty low pressure switch or a partially restricted orifice tube.

 

[Studio54]

I've heard about the orifice tube and haven't checked it. But it runs constantly even with the ac button not pressed. When I have it on defrost and it's not on ac it freezes up quicker. I just am getting frustrated and trying to figure it out.

So I should try to replace the low pressure switch first?

 

[1997chevydriver]

If you have it on defrost it WILL be on but is supposed to cycle if it is cold temps outside. Does it come on on the vent setting or the floor?

I would unplug the low pressure sensor and if the compressor still turns on you have wiring problems somewhere. if it does not turn on I would replace the LP switch

 

[Studio54]

It works on all vents at any speed at all times. Ac compressor is ALWAYS running wether ac is selected or not. Defrost or not.

It doesn't cycle either. Just constantly runs then ices up extremely fast. New compressor and piping too.

Also want to note that it has the correct amount of refrigerant in it as well. Already checked that.

 

[1997chevydriver]

You have some bad wiring somewhere or something. A bad lp switch won't cause that. I wouldcheck for pinched wires.

Also is the a/c light all the time?

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[Studio54]

You have some bad wiring somewhere or something. A bad lp switch won't cause that. I wouldcheck for pinched wires.

Also is the a/c light all the time?

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Looks like its somewhat lit but not as bright as if I were to actually turn it on.

Also I've replaced the hvac controls so it's not the switches.

 

[1997chevydriver]

Looks like its somewhat lit but not as bright as if I were to actually turn it on.

Also I've replaced the hvac controls so it's not the switches.

If its "somewhat lit" i would start looking for a bad wire that is getting power from somewhere its not supposed to.

Did this start after compressor swap? If so check for pinched wires by the compressor. The reason i say that is because i don't remember if the compressor has power all the time, if it does then it works off a switched ground.

so if the ground wire from the clutch is pinched and shortened to ground it may bypass all other switches.

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[Studio54]

If its "somewhat lit" i would start looking for a bad wire that is getting power from somewhere its not supposed to.

Did this start after compressor swap? If so check for pinched wires by the compressor. The reason i say that is because i don't remember if the compressor has power all the time, if it does then it works off a switched ground.

so if the ground wire from the clutch is pinched and shortened to ground it may bypass all other switches.

Sent from my N860 using Tapatalk 2

I'm replacing the radiator this weekend because ty connections from GM at the radiator so I'll have the hoses off that cover up the AC wiring and check it all out.

I got the truck with it replaced so sadly I'm just tracking down other things. I know it pukes a bunch of water as soon as I turn the truck off as well.