van44

2005 Chevy 1500 4x4 with 5.3L

My air conditioning has stopped cooling and its so hot here both of my children are getting sick in my truck and i just cannot keep going on like this anymore!!!!!

My a/c clutch stays engaged no matter what the pressure or how much refrigerant. I have changed the orifice tube, 2 wire Low pressure switch and the three wire Pressure sensor and charged the system. The high side is high and the low side is high but like I said the compressor keeps on running no matter what! Unless I unplug the comp cycling switch (Low side switch).

I think my whole problem is that the comp clutch isn't cycling on and off. It just says on constantly no matter what i do causing the system to not cool properly by keeping such high pressures. I cant figure out how to get it to cycle correctly even though Ive changed the sensors, orifice tube and charged the system.

If it wasn't for my kids this wouldn't be URGENT but they are just dying in this heat! Any help would be greatly appreciated. Thanks!

This is what i have done/checked

I have charged it to 1.6lbs still no change
If i had too little refrigerant the clutch would/should not engage if i had 2 much it shouldn't engage. (I have evacuated the system and started the truck with a vacuum absolutely no-ZERO- refrigerant -and the clutch continuously runs w/o cycling) i have charged it to spec, under charged it and over charged it but the clutch still continuously runs without cycling

I have replaced the relay with no change

i have replaced both inline sensors and orifice tube with no change

I have scanned the sensors and they are working properly.

I have checked for a wire short w/no luck.

my scan tool is showing codes B0164 and B0229 but have no idea what that has to do with the clutch not cutting on and off. Whats next? Any help would be greatly appreciated.. Tks

s34n

DTC B0164 Passenger Compartment Temperature Sensor #1 (Single Sensor or LH) Circuit Range/Performance
DTC B0229 Air Flow Control #7 (Recirc) Feedback Circuit Range/Performance I.
thats what the codes mean im not sure about the 2nd code. but sounds like the 1st code is implying that the temp sensor needs to be replaced. let alone checked.

MDTAHOE

depending on the temp and humidity some systems do not cycle. How have you vac the system? What are the pressures? Did you weigh in the charge?

van44

I did not know that about the clutch not cycling in hot weather.

Yes i pulled a vacuum and charged the system to spec 1.6 lbs
I don't know what you mean by how i vac the system but i pulled it down to 29 inhg checked for leaks . Found none and recharged.

pressure is high on low side and high on high side

70+ lbs to retard on low side and 300-390 high side.

(I have evacuated the system and started the truck with a vacuum absolutely no-ZERO- refrigerant -and the clutch continuously runs w/o cycling) i have charged it to spec under charged it and over charged it but the clutch still continuously runs without cycling

I believe the compressor is fine it does take a charge (sucks the refrigerant in) and pressurizes the system. Also with the low side switch unplugged the clutch disengages and the pressures drops/fluctuates..

I did notice when I removed the orifice tube that the evaporator released a bunch of pressure rapidly and then just stopped. It didn't dump the pressure out then gradually hiss out the rest of a lower pressure. Almost like something restricted the line or evap. But i didn't /don't know if this is normal because it is a rather large line. Every other line I removed dumped out pressure then hissed to a stop.

So do i need to flush the system or at least the evap before moving any further?

van44

a little info on the o-tube and a quick question about the 2 wire low side switch........

It did have some metal shavings on it but the screens were not plugged up. You could see through them. The few metal shavings I did see I just figured it was from the compressor over running/over doing it double time.

The blue wire (or maybe it was the black one) has a 5 volt ref to the switch and never sends voltage to the other wire. This I have checked..... So I assume it just grounds the other wire internally in the switch turning the comp on right?