HVAC help

[Spectracular]

New here, but looking for help. I have a 2001 Yukon (4.8l) with an AC issue. The front ac blows Luke warm, while the rear ac is noticeable colder. My car has the single zone automatic control for the front.

The AC was ice cold at the start of a 200 mile road trip, and then suddenly stopped cooling the next day. No warning or anything that would have indicated there was an issue.

• I checked that the blend door motor at the very bottom of the dash is working. It is.
• I also manually moved the post that that controller connects to in order to ensure that there was no obstruction. In one position the air from the front vents is hot, and then rotated the other way, the air cools down to about ambient, maybe a touch cooler.
• Cabin air filters were very dirty...blew them out with compressed air for time being.
• Ac compressor cycles about every 10 seconds at 1800 rpm
• Hooked up gauges under the hood (1800 rpm) low side swings from 17 to 65 as the compressor cycles. While the low side builds pressure, the high side drops to about 105. While the low side drops, the high side peaks around 130.
• No scary noises.

Thoughts? It was about 78 degrees out and 50% humidity.

 

[Spectracular]

 

[exp500]

Sounds like you are low. Recommend you download/ get a temp/pressure chart for R134 and keep with your kit. Helps sometimes to have a laser thermometer so you can watch discharge and dryer temps. It's cycling too fast. If pressures seem right, spray water on condenser, that will show plugging or condenser not doing its job.

 

[Spectracular]

Sounds like you are low. Recommend you download/ get a temp/pressure chart for R134 and keep with your kit. Helps sometimes to have a laser thermometer so you can watch discharge and dryer temps. It's cycling too fast. If pressures seem right, spray water on condenser, that will show plugging or condenser not doing its job.

10-4. Thank you. I figured it was low due to the frequent cycling. I’ve only done the hvac 1 other time in my life...different car...so this is still very new to me.

 

[swathdiver]

@91RS @Scottydoggs