Low pressure ac switch location

[BG1988]

Thank you for posting that. Does the refrigerant need to be evacuated to change the switch?

maybe you risk getting some moisture into the system though

 

[Cjherndon]

Since my evaporator is freezing up, I’m assuming the switch is stuck open (you know what happens when we assume? Is there a chance if it’s stuck open, when I remove the switch, there is nothing to keep the refrigerant from free-flowing out?

 

[wjburken]

Since my evaporator is freezing up, I’m assuming the switch is stuck open (you know what happens when we assume? Is there a chance if it’s stuck open, when I remove the switch, there is nothing to keep the refrigerant from free-flowing out?

@UmmScott might be able to walk you through some troubleshooting steps to make sure you are on the right path.

 

[Cjherndon]

I’m happy for any advice: this is what has been done so far.

Evap and Dryer freezing up, but only on lowest 3 fan settings. I checked refrig level and it’s perfect. I had the system evac’ed, power flushed, and the oriface tube replaced. I also had the computer re-flashed to an upgraded AC program.
Did not fix the problem.

I would physically turn the compressor off by turning the AC off in the cabin. Let it thaw out, then turn it back on. After a few reps of this, the compressor refused to turn back on.

After parking with the motor off for about 20 min’s the compressor will start but back to square one with the freezing on lowest fan speeds.

From my research (not claiming to be an expert by any stretch), I think it either has to be the AC pressure switch or the evaporator temp sensor.

im hoping it’s the pressure switch under the hood instead of the evap temp switch behind the dash.

Any advice will be appreciated. I’m certain I’m the least knowledgeable of anyone on this thread.

thanks in advance.

 

[gooffeyguy]

Do you have a cabin air filter installed? If so, have you checked it to make sure it's not dirty and blocking airflow at lower fan speeds?

Sent from my SM-G930V using Tapatalk

 

[1BADI5]

Yeah mine is acting up too.

It will be nice and cold sometimes, and other times I'll get 80* air out of the vents. Going to the shop later since I can work inside and try to diagnose the issue

 

[Cjherndon]

Yes, I retrofitted a cabin air filter. The coils were pretty clean, but I cleaned them even so.

 

[TheBigDirty]

Evacuation of the refrigerant is not necessary. There is a schraeder valve that closes off the system when the switch is removed. As stated though, you will get a little puff, possibly more if you take your sweet a$$ time unthreading the switch from the port.

Only one switch is listed under ac pressure switches for my 13... if I do find my low pressure switch as the service manual shows... are these dual pressure switches? In other words, can the same switch be used on high or low ports?

 

[TheBigDirty]

I finally got a chance to look at mine again today, and according to the picture in that service manual, I did in fact replace the low pressure switch. What I maze of piping that I cant see down there. I woulda bet money on that being a high pressure switch given its location and the routing of the piping.
Time for more guessing on what is wrong... I guess

 

[96-2D-Hoe]

LP switch is normally to stop the system running into a vacuum when refrigerant is lost. I'd be very surprised if that fixes this issue. But I have 0 experience on this model AC.

Low airflow, low refrigerant charge, or a bad expansion device would normally be the only reasons the evaporator would freeze up.