AC Turns Itself On

[CLOSERHawk]

Happy Hump Day!

 

The problem goes a little something like this; Some days when I am driving, I will turn the fan off and roll down the windows or open the sunroof. Keep in mind, when I am turning the fan off the AC is not on, nor is the light lit up indicating that it is on. I'll park my truck and get out. When I return to my truck the next hour or day, I'll get in the truck and turn on the fan. When I turn on the fan, the AC automatically turns itself on as well at that instant. This only happens when the fan is turned off and I turn the truck off and then turn it back on and power on the fan. It's a minor annoyance. Was curious if any of you all have noticed this? If so, is there a setting that can disable this that you have found? In the colder season, I really hate getting out on the road after pulling out of the garage and turning the fan on and turning the temperature up and finding 5 minutes later that the AC has been running.

 

Thanks!

[mzodarg]

Do you happen to have "Auto" on when this happens? I ask because I've done this before myself.

 

Mike

[CLOSERHawk]

Do you happen to have "Auto" on when this happens? I ask because I've done this before myself.

 

Mike

 

Great question. I do not have auto on. I've never used it.

[mzodarg]

As I said it happened to me. I was like WTF but then figured it out.

 

Mike

[idahoruss]

Most newer vehicles run the AC to dry the air, especially during cold weather when the defroster is on. This is a default setting so it would probably turn on the AC when starting the engine. Since I have not been a mechanic for many years, I might be wrong on the default idea. I think it is better for the AC pump to run, since this will keel the compressor seal from leaking as it would tend to do when sitting idle.

 

Russ Johnson, old auto mechanic.

[CLOSERHawk]

Most newer vehicles run the AC to dry the air, especially during cold weather when the defroster is on. This is a default setting so it would probably turn on the AC when starting the engine. Since I have not been a mechanic for many years, I might be wrong on the default idea. I think it is better for the AC pump to run, since this will keel the compressor seal from leaking as it would tend to do when sitting idle.

 

Russ Johnson, old auto mechanic.

 

Hey Russ. Thanks for the information. Interesting tidbit here: My truck is parked in a heated garaged and my defroster is not on when I get in and turn on the truck. Because of this, there is no need to even run the heated seats, let alone the defroster!

[2014Z71LTZ]

Mine does the same thing, it kinda pisses me off. $50,000 on a truck and it does this.

Doesn't seem to matter if auto is on or not, only way it seems to stay off is if you don't turn off the fan when you turn off the truck.

[2014Z71LTZ]

mzodarg, is that a Z71 with a chrome grill? Haven't seen one like that yet, every one I've seen has the black grill.

[mzodarg]

mzodarg, is that a Z71 with a chrome grill? Haven't seen one like that yet, every one I've seen has the black grill.

Yes it's a Z71, dealer replaced the grill at my request. I then took the z71 off the old grill and did some minor mods to it (drill some holes) and put the Z71 emblem on it.

 

Mike

[CLOSERHawk]

Mine does the same thing, it kinda pisses me off. $50,000 on a truck and it does this.

Doesn't seem to matter if auto is on or not, only way it seems to stay off is if you don't turn off the fan when you turn off the truck.

 

This. I KNEW this wasn't a fluke thing.

[redwngr]

AC is also used for humidity control. Just cause the light is on does not necessarily mean the compressor is running -- only that the system is enabled.

[CLOSERHawk]

AC is also used for humidity control. Just cause the light is on does not necessarily mean the compressor is running -- only that the system is enabled.

 

Hey redwngr, do you own a 2014 Silvy or Sierra?

[redwngr]

Still debating, and running 2011 Sierra SLT CCSB, Dmax 4x4 Z71.

 

No longer require Dmax towing capability and considering whether to go to 1500 (possibly max tow) or wait for NNBS 2500.

 

Many discussions here are similar to those on the late model sections of the dmax forums.