Chevy Silverado and GMC Sierra Forum banner
Cancel
Create thread New Garage Forums

A/C Button Flashes?

Jump to Latest
289K views 45 replies 24 participants last post by  kellynkacey  
#1 · (Edited by Moderator)
Okay, this morning I turned my climate control to Auto. Usually, the A/C light turns on. But this time, it flashed 3 times and then went off. Then I pushed the A/C button to turn it on manually, and it flashed 3 times again and then turned off.

What the heck is going on?

Thanks
 
#6 ·
When the temperature is very cold the ac compressor will not come on. That is why you get the flashing light. The ac system KNOWS it is cold outside due to available pressure in the system. Cold weather, low pressure, the pressure switch does not close and the compressor does not come on and you get the flashing light. BUT...................even in winter or cold temperatures, the underhood engine heat can heat up all of the ac system plumbing and raise the pressure to close the switch and it MAY come on and work till the underhood temp goes back to cold again. So yes it appears that your system is working as it should, assuming last summer it was blowing cold air for you.
 
#10 ·
Okay, Austin, let me explain............

When the Auto function is selected it automatically turns on the a/c (for some unknown reason) and it only does this when the front defroster is on. I typically turn it off every time I get in the truck because it automatically comes on, this is why it struck me funny when it started blinking.

When you have more technology, it leaves room for more crap to go wrong....
 
#11 ·
My Honda Civic Si ran the compressor when it was cold to dry the air being used to defrost the window (no indication that it was on but you could feel the compressor kick o and off). I am guessing that GM does not do this then.......
 
Save
Reply Quote Like Like
#12 ·
If I recall, the compressor will not run in the "Auto" mode; I think it does run in the "Defrost" mode.
 
Save
Reply Quote Like Like
#15 ·
Trumpster1 said:
Okay, this morning, I turned my climate control to Auto. Usually, the A/C light turns on, but this time, it flashed 3 times then went off. Then I pushed the A/C button to turn it on manually, and it flashed 3 times again then turned off.

What the heck is going on?

Thanks
Click to expand...
I had a similar issue yesterday when I tried to turn the AC on and it flashed three times then went out. I read in the manual and it explained that the outside temperature must be above 40 degrees or the compressor will not be allowed to engage. The problem was that it was 65 degrees outside however my outside temp sensor was stuck on 34 degrees from the morning.

I called my dealer today and the service rep told me that the truck has to be driven above a certian speed before enough air can reach the sensor and cause it to adjust to the current temperature. later this afternoon we took the truck out on the highway and sure enough the temp display quickly zoomed from 60 to 75 degrees which was the current temp.

The service rep said that he had a lady bring in a new Buick with the same problem yesterday. He took her out on the highway with it and the outside temp desplay quickly zoomed from below freezing to the current temp and thios allowed her AC to stay on.

The service rep said that this new system has been on GM cars and trucks for about 3 years now. Go figure. Sure does not sound like very good system to me. Give me back the old system.
 
#16 ·
rdss said:
My Honda Civic Si ran the compressor when it was cold to dry the air being used to defrost the window (no indication that it was on but you could feel the compressor kick o and off). I am guessing that GM does not do this then.......
Click to expand...
my truck does the same thing, not sure why the new ones wouldnt...
 
Save
Reply Quote Like Like
#17 ·
I need to read more of my owner's manual... the same 'flashing' happened with the recirculate button and the pass button to me. I don't recall what the other settings were on, nor did I record the outside temp, but it seemed very odd to me.

Jim
 
#19 ·
I couldn't agree more. I bought one for mine!

The GM 100k drive train warranty will likely never come into play on these trucks however those pesky electronic repairs can put you into the poor house...
 
#20 ·
So far, I have set mine at 70 degrees, and never changed it. I take that back...I hit the defrost button once to clear the windshield. I like the way the climate control works. Just set it, and forget it. I will probably just have to adjust the temp for summer, but other than that, I do not mess with it much. It seems to know what I like.
 
Save
Reply Quote Like Like
#22 ·
Yep,

If the truck thinks its below 40 degrees outside, your AC will not be allowed to come on to protect the compressor. Go figure!! The darn AC light will just flash on and off.

I ran into this problem in the spring when the temps would drop below 40 degrees during the night, then shoot back up to the 70's during daytime. What componds the issue is that the ambiant temp sensor is located in such a place that it would not get enough air to adjust from the low night time temps without driving at hwy speeds.

My Chevy service tech advised me to press the recirculation button and the AC button (just below it) at the tame time to get the ambiant temp reading to instantly reset the computer to the current actual temp. This allowed us to have AC once again as long as the outside temp is above 40.
 
G
#24 ·
Hopefully I am not asking too stupid of a question, in the winter, I use my ac to reduce the fog on the inside of my windows. When it is warm in the cab and u have snow on u, the humidity builds up and Fogs the windows. I just wasn't sure if there is a way to "force the ac on to remove the steam on the inside of the windows when it is below freezing.
 
B
#25 ·
i am having the same problem as some of you. Except that i live in florida, it is 69 and raining and my light flashes 3 times and the a/c doesnt come on. it got warm in my truck fast and my damn a/c is not working. any thoughts on my issue. also i did hit highway speeds for about 5 minutes with no change.
 
#26 ·
Billy,
Press the AC & Recirculation buttons simultaneously with your index & middle finger. (The recirculation button is right above the AC button). This causes the an instant temperature update to your system and allow your AC to come on and stay on afterwards. My Chevy service rep. looked up the problem on his GM computer while I stood there, then he printed this solution off for me.
 
Chevy Silverado and GMC Sierra Forum
posts
1.5M
members
232K
Since
2009
A forum community dedicated to Chevrolet Silverado and GMC Sierra pickup owners and enthusiasts. Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
Vortec 5300 5.3L V8 Exterior - Body - Frame Suspension - Steering ⛐ Electrical ⚡ Uncategorized Truck Topics 🛻