A/C light blinks 3 times and won't engage or turn on

[Jetfumes]

Need some help. My battery died two days ago, and I replaced the battery, ever since my A/C won't engage or turn on. A/C was working before dead battery

I have a 00 GMC Yukon XL SLT with automatic climate control with rear climate control. I have removed all the HVAC &AC fuses and relay's to see if it resets itself. I have also tried holding the recirc and AC buttons at the same time to reset ambient temp.

Outside temp is 84F

Any thoughts?

 

[NathanJax]

Try this...

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.

 

[Rocket Man]

The 3 blinks usually means something isn't in the correct position for the A/C to operate- either the mode control is in the wrong position (a/c doesn't work in defrost mode, etc.) or the compressor won't turn on for some reason. There is another reset procedure other than the one Nathanjax mentioned- first start it up and set all hvac controls to off, then shut off the engine, disconnect the positive battery cable, wait 10 minutes, then before reconnecting it touch it to the negative battery post for a complete discharge of the system. Reconnect the cable and start up the engine but don't touch the hvac controls for at least 5 minutes during which time all the actuators (mode, blend, recirc) recalibrate. After 5-10 minutes, try the a/c. This is the only thing that has worked for me in the past after I changed out parts of the system.

 

[Rivieraracing]

Great advice, will have to remember this for the future!

 

[Jetfumes]

NathanJax I tried the Recirc and AC reset and that didn't work.

RedRocket I will give that try, and update the group.

I think this may be the trick since I had to change the battery and previous battery was dead.

Thanks again.

 

[Jetfumes]

RedRocket your fix worked like a charm and saved lots of money. I appreciate it. Your tip probably should be in the tech info area.

 

[Rocket Man]

RedRocket your fix worked like a charm and saved lots of money. I appreciate it. Your tip probably should be in the tech info area.

Done. I'm really glad that worked for you!

 

[PeterD]

Need some help. My battery died two days ago, and I replaced the battery, ever since my A/C won't engage or turn on. A/C was working before dead battery

I have a 00 GMC Yukon XL SLT with automatic climate control with rear climate control. I have removed all the HVAC &AC fuses and relay's to see if it resets itself. I have also tried holding the recirc and AC buttons at the same time to reset ambient temp.

Outside temp is 84F

Any thoughts?

I have a 2010 Yukon - same issue.
Had the ac all checked out - all good.
I warmed the vehicle up to about 7 celcius where we are now above the trip point (2c) where my ac would not work.
With vehicle turned off, I then removed the ambient temperature sensor from behind the grill.
All the computer remembers is the last reported temperature, so the ac comes on now any time I want it - mainly I needed it for de-fogging.
While I don't have the temperature indicated on the dash anymore, I do get my ac whenever I want.
In summer, I'll just put the temp sensor back in place.
Cheers,

 

[Rocket Man]

I have a 2010 Yukon - same issue.
Had the ac all checked out - all good.
I warmed the vehicle up to about 7 celcius where we are now above the trip point (2c) where my ac would not work.
With vehicle turned off, I then removed the ambient temperature sensor from behind the grill.
All the computer remembers is the last reported temperature, so the ac comes on now any time I want it - mainly I needed it for de-fogging.
While I don't have the temperature indicated on the dash anymore, I do get my ac whenever I want.
In summer, I'll just put the temp sensor back in place.
Cheers,

Did you try my procedure first before going to that extreme?

 

[Crazyk]

The 3 blinks usually means something isn't in the correct position for the A/C to operate- either the mode control is in the wrong position (a/c doesn't work in defrost mode, etc.) or the compressor won't turn on for some reason. There is another reset procedure other than the one Nathanjax mentioned- first start it up and set all hvac controls to off, then shut off the engine, disconnect the positive battery cable, wait 10 minutes, then before reconnecting it touch it to the negative battery post for a complete discharge of the system. Reconnect the cable and start up the engine but don't touch the hvac controls for at least 5 minutes during which time all the actuators (mode, blend, recirc) recalibrate. After 5-10 minutes, try the a/c. This is the only thing that has worked for me in the past after I changed out parts of the system.

Thank you so much for this. Fixe my problem! Lots of time spent searching before getting to here. Thanks again!