? low pressure ac pirt on 00 gmc yukon?

[Soundguy]

Yukon not blowing cold air, though IS cool. Compressor does cycle on, it I not a fast on/off, however it does nit stay on for an extended time either, small metal line dies get cold.

Large line from comp to evap is a big flexible one like a hyd hose, snall line has 2 ports, one with a red cap labeled H ( high ores I assume since it is the small line). And on the sane line, after a fitting union, a black cap, those are both on the small line, only Schrader valves I can see, what am I missing, gm do something weird? I have one of those 1 hose kits I was just going to throw the gauge on, nit even add.. Just see pressure, ny lil book says fir 95 ' temp. Low did pressure 55 psi.. But I can't find the darn low pressure Schrader valve

 

[WM75Guy]

I just had my 03 GMC in the shop. It would blow cold running done the road but if I stopped it at a light it was barely cool. Mechanic had to loosen the condenser and clean between it and the radiator. It was solid mud and stuff so that hosing it off thru the grill did no good. It blows cool now. I have never had to add Freon since day 1.

 

[Soundguy]

Replaced ead in truck a few months ago, so that is probably not it

 

[The Fred]

GM should have both high and low side valves, they always do. If there is any pressure in the system it most likely needs a charge. If there is no pressure is because it has a leak.
Proper would be evacuate and recharge with proper amount, weight.

What year? Rear AC?

Cold should be about 43 degrees coming out the vents.

Fred

 

[Clint S]

Most of the time low pressure side will be blue or black cap, Chevy may have 2. The high pressure cap is larger and the fitting "should not " fit on it. They may be near the accumulator near the passenger firewall. ps I am no expert just trying to remember what was on dads 2003 truck

 

[tractortom55]

Orifice is between both fittings. The one after the bend closest to firewall is low side and has Schadder valve. The high side looks like it has a small ball it.

 

[Soundguy]

The two caps are on the sane tube, small ones
near firewall

 

[Soundguy]

Went and looked again, small tube has 2 ports, a connect seperates them, they are about a foot apart, black cap is close to the firewall, has a plunger style valve, red cap closer to front of vehicle with a ball in center of valve. I'm no ac guy, just figured they would be on different lines?

 

[tractortom55]

There is an orifice tube in that fitting and that is where the pressure change is made from high to low.

 

[Soundguy]

You guys are good

That was it, pressure was a little low, guage just had white, green and red, with a lil dial to manually choose ambient temps, then it shows a v the needle should be in, needle was upper middle white, used the can it came with, got it to the green, she went from blowing cool, to blowing cold, will keep an eye on pressures to see if she I leaking

Thanks