2013 Yukon Rear A/C Operation?

[micdoctr]

I have a 2013 Yukon Denali with dual climate control. A/c didn't work last week suddenly, so i had it recharged and put a/c dye in it to find a potential leak. 2 days later, i see a puddle of yellow/green dye under the truck in the morning. Bought a uv/black light and got under the truck and i can see where the dye is coming from, there is a half-inch long gash in the aluminum low-side a/c line where it goes over the shock housing. Looks like the a/c line is sitting right on top of the steel bracket and wore a hole in it.

I plan on fixing this piece of line, but was wondering why the front a/c system still blows cold when i have the rear system in the off position (rear button is off). The low side and high side a/c lines run from front to back, and was wondering what happens when you hit the rear a/c button on the front control panel? Does anyone have an explanation of how the front and rear a/c systems work? I am looking for what happens after you hit the rear button, does a solenoid switch on and send freon to the rear system?

I am thinking the rear system only works when you hit the rear button, but they both use the same components like compressor, condensor, drier, but have different evaporators.

Anyone have an explanation of what happens when you hit the rear a/c button? Thanks

 

[Doubeleive]

my guess would be it still currently has enough cooling capacity for the front but by the time it reaches the back it looses it's oomph, hitting the rear a/c button simply turns the fan on/off and commands the blend door to hot or cold. It does not control flow of the Freon or coolant, when the compressor is going it runs thru the entire system

 

[micdoctr]

I get that it is one low side and high side line running from the front to the back, but the front is still cooling and it is a week later now. The rear low side line going over the back of the rear end still has the leak, but we have not been using the rear a/c controls when we drive it. Seems to me if the freon is making a front to back trip on the low side constantly, then all of it would have leaked out by now?

 

[Moose912]

Once free on leaks out enough the front will stop too,(obviously). As said before, although there are two lines, there is enough to cycle right now and will continue until it’s gone/low

 

[micdoctr]

Update on this issue, the freon leaked back out in about a month. Saw a puddle of green dye right behind the right rear tire and got up under the truck with a flashlight to take a look. The low side (smaller diameter) aluminum a/c line was sitting right on top of the shock mount and had worn about a half inch gash into the aluminum line. The freon was leaking out at that spot which is why it took so long for it to leak out. I ordered this a/c repair line and took off the right rear wheel, pulled back the wheel well liner and cut the bad section of line out with my hose cutter. Repair line went in with no issues besides me second guessing where to cut, as i cut it a few different times to get the length correct. I got the 12inch hose and there is plenty of line left. Kit i bought is below in case someone else has this same issue: https://www.autocoolingsolutions.com/ac-lines/a-c-line-repair-kit-3-8-tr6

 

[SPDMETL]

Thanks for posting this...our 07 SLE just had a similar issue and the stealership offered 2 options

Cap and recharge leaving front only-$600ish

Proper repair-$1,300ish

If I had only read this before it went in