A/C pressure sensor switch location

NALTER27

MEMBER
2013 CHEVROLET SILVERADO
4.8L
V8
2WD
AUTOMATIC
100,800 MILES

A/C clutch is staying on. So when driving down the road after 15 minutes I think it’s freezing up and I lose A/C. Still feels cold but isn’t blowing much and sounds like my blower motor isn’t getting enough air. I replaced the blower motor, blower motor resistor, and blend door actuator. So my next guess is the pressure switch, but can not locate it. Any suggestions?

4 Replies

KASEKENNY

MECHANIC
18,907 POSTS

The pressure switch is on the high side line near the compressor. I think you are on the right path that the evaporator is freezing as this will decrease air flow from the vents as the iced over evaporator will not allow as much air through it.

I attached the location of the switch. The best way to confirm this is to check the pressure of the system as low refrigerant will also cause this.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Let me know what you find and we can go from there. thanks

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Saturday, July 25th, 2020 AT 1:45 PM

NALTER27

MEMBER
3 POSTS

Okay, I found it! Thank you! Picking the part up at the auto store and changing it out now. Hopefully I don’t also have to do the electrical connector/wiring as well. Will update when I install it. Just unplug, and use a wrench to remove and install the new one and plug electrical connector back in I’m assuming? Don’t need to uncharge the system or disconnect negative battery terminal?

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Saturday, July 25th, 2020 AT 1:50 PM

NALTER27

MEMBER
3 POSTS

Looks like the new pressure switch didn’t work. Accumulator still freezing up. Any suggestions now?

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Saturday, July 25th, 2020 AT 6:18 PM

KASEKENNY

MECHANIC
18,907 POSTS

If this is freezing up we need to start with checking pressures. The leading cause of it freezing is a low charge however, if just the accumulator is freezing, I suspect the filter inside of it is restricted or blocked. Also, there could be a large amount of moisture in the system caused by a leak which is why we need to check pressure and then pull it down into a vacuum to make sure it can hold it for about an hour.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

So the next step needs to be checking the pressure, pulling the system into a vacuum and then charging it properly to ensure it is not low then recheck to see if it is freezing. If it is then we have a restriction.

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