drewtx154
Member
so my Tahoes rear ac isn’t blowing cold air, only air temp air. When I first bought the truck back in 2022 the rear AC did work but soon after it stopped blowing cold. Keep in mind that the front blows well and can cool the entire vehicle on a very hot day after given enough time to properly circulate through the large interior. Never the less I would prefer the entire HVAC system to work as intended or as close to as intended as possible. I do have actual manifold gauges and I did check the system with gauges and the pressures were within spec I believe (can’t remember the exact readings) at the time. But I can recheck. I did the “touch and feel” method on the AC lines and I only get warm lines nothing cold. At first I thought it could be a blend door problem but getting under the truck and not feeling ice cold AC lines like I can feel from the lines under the hood makes me suspect a clogged TXV valve in the rear unit. Although when testing out the blend door actuator and watching it rotate the blend door shaft I notice that mine only rotates what seems like not enough to totally switch the blend door to a cold setting. I really have no idea how much it’s supposed to turn but just common knowledge leads me to believe it may not be moving the blend door the fully as it’s supposed to. The actuators outside case has reference lines as to the amount of rotation the actuators supposed to make, well when turning mine from the fully cold position to the fully hot position only makes the shaft rotate half the distance on the reference points and I included pics with notes to show what I’m trying to explain in case some may be lost(I’m not very good at explaining while typing or talking for that matter lmao). But anywho what experiences, tests, procedures could you guys suggest to me to help me fully diagnose this issue so I’m not just throwing parts at it and praying that it’s the right path I’m taking. Also I don’t have the luxury of a limitless budget on this repair as it’s quite the opposite…lol. Also note that I’m guessing the previous or maybe the previous previous owners had already bypassed the heater core and again I’m guessing because of a leak in core but I’m not 100% is just a logical guess. Also compressor clutch pulley was also changed but not the electromagnet (is that the proper term?) because I couldn’t get snap ring off and the one on there wasn’t bad or showing any possible issues. New clutch pulley was properly gapped with feeler gauge according to the info I gathered online and all was good after and since with the compressor
