Automotive Air Conditioning Information Forum

Just wanted to say hi. I have some experience in replacing ac systems in couple of my cars and even installing new ones in engine swapped vehicles.

Recently I bought a 2000 suburban. It has front and rear ac. It also has the high side and low side ports on same line with orifice tube in-between. Something new to me( worked on expansion valve systems)

Here is the symptoms. Ac blowing cold then just blows ok. Not hot but not super cold.

Fan speed was only working on 3 and up (prob needs fan speed resistor changed)

When using the temp control dial and go from hot then eback to cold sometimes it would stay hot. (Most likely blend actuator underneath)

Rear ac only blows warm (I've been told it has expansion valve setup in the rear)

So other day it stopped blowing super cold all together while on highway.

My most recent guages readings where 85° outside
Low side 50psi and high side 250psi

When the checking the static pressure of system they're both at 80 (ac system not running vehicle off)

Thoughts on some things to check. I'll be doing some trouble shooting this weekend.

Rlfdavin wrote:When using the temp control dial and go from hot then back to cold sometimes it would stay hot. (Most likely blend actuator underneath)

We HAD a 1994 Suburban and HAVE a 2005 Yukon XL (both factory R134a); both had malfunctioning actuator causing temperature to go from real-cold to hot, and that's bad in Arizona. For the 1994 had a shop repair it, it was over $300. So when similar occurred on the 2005, I did the fix myself.

Toughest part was removing the under-dash cover, had to shorten my 5.5mm socket at both ends for clearance/fit. My bad actuator (there are about 3 of them) was passenger side under the dash, closest to the hump. I didn't buy factory part, I matched with Dorman part at half price. After the install, there's a procedure (on Internet) to get the computer to recognize the new part. Good several years now.

Also confirm that the compressor drive plate (the center part) is turning when the AC system runs hot, not just the outer pulley.

Thanks! I'm looking to do that exact replacement.