A/C fan won’t kick on

[GMswin13]

Hello I’m fairly new here I’m not sure if I’m posting in the right area so forgive me.
I have a 2016 Yukon XL 5.3 2wd it’s been having electrical issues in the past year the headlights would always pulsate almost like flashing your headlights bright to dim. Just the headlights. Well one day it just stopped few months back. Especially when the fan would kick in but anyway the AC fan won’t kick in when I turn the ac on its full of Freon and I can see the compressor kick in. I also checked the fuses all good. Both fans are working I just checked them there on low as the engine runs. There’s only 2 fans that I can see. Back in the winter I went through and cleaned all ground connections that I can find I gotta get this figured out it’s my wife’s daily. I haven’t ran any codes and no engine lights on. Has anyone ran into something like this?

 

[Fless]

Are you asking about the radiator fans? Or the HVAC fan?

 

[GMswin13]

HVAC fan when you engage the AC button the fan kicks on high it don’t do it now. The compressor kicks in and the inside blower motor works fine the ac will cool down if I’m going 75mph on the interstate state that’s it.

 

[GMswin13]

Thanks for the help

 

[GMswin13]

This is about a dead fourm ain’t it?

 

[Fless]

Personally I'm having a difficult time figuring out what the complaint is. Maybe saying it another way, or in simpler terms, would help my feeble mind.

Is it that the HVAC fan used to turn on at high speed when you engaged the A/C, but now it doesn't?

 

[blondie70]

I think he's talking about the cooling fans. (but not sure)

 

[GMswin13]

Yes sir the fans don’t kick on high when I turn on the AC you know it sounds like a 747 when there on high when you turn the ac on. The compressor turns on and Freon is full and good.

 

[Doubeleive]

Hello I’m fairly new here I’m not sure if I’m posting in the right area so forgive me.
I have a 2016 Yukon XL 5.3 2wd it’s been having electrical issues in the past year the headlights would always pulsate almost like flashing your headlights bright to dim. Just the headlights. Well one day it just stopped few months back. Especially when the fan would kick in but anyway the AC fan won’t kick in when I turn the ac on its full of Freon and I can see the compressor kick in. I also checked the fuses all good. Both fans are working I just checked them there on low as the engine runs. There’s only 2 fans that I can see. Back in the winter I went through and cleaned all ground connections that I can find I gotta get this figured out it’s my wife’s daily. I haven’t ran any codes and no engine lights on. Has anyone ran into something like this?

can you see the problem below???? what gives?
you said: quote.....
Both fans are working I just checked them there on low as the engine runs. There’s only 2 fans that I can see.
HVAC fan when you engage the AC button the fan kicks on high it don’t do it now
the fans don’t kick on high when I turn on the AC

so PLEASE clarify concisely what the problem is otherwise no one can help you when you make contradictory statements back-to-back

if the hvac fan (the inside passenger side dash/under behind the glove box) does not turn on then you need to pull it out and test it and check fuses.
then proceed accordingly.....

if the fans in the engine compartment do not kick on then you may have either a hvac issue or perhaps a sensor is not working, could be many things really.

 

[Doubeleive]

and it's not that the forum is dead, nobody is going to answer when they can't make heads or tails of what the problem is...

 

[BattleTank]

How did you verify the freon is 'good'?

 

[GMswin13]

Ok I’m not sure how more clear I can be.
The blower motor works fine the one behind / under the glove box. The 2 coolant fans in front of the engine attached to the radiator/condenser are always on low when the engine is running….now say you wanna turn on the AC turn the blower motor on high hit the A/C button the COOLANT FANS normally turn on high periodically all vehicles do this I’m not sure why it’s confusing.
In my case when I hit the AC button everything works fine but not so cold air cause the coolant fans won’t kick on high.. I’m trying to figure out if anyone has ever had this issue… I’m not sure how else to explain this other than making a video

 

[GMswin13]

How did you verify the freon is 'good'?

All I did was attempt to fill it with a Freon can that had a guage and it was reading right where it needed to be

 

[Doubeleive]

so basically all you get when you turn on the ac is hot air?
if so then you need to have some deeper trouble troubleshooting performed by someone with a gauge and/or scanner tool to determine what exactly is happening.
it could be a sensor, could the hvac controller, etc
do either of the hvac pipes under the hood that enter the firewall feel cool/cold or warm/hot? do they look frozen? any moisture/sweat on them?

 

[Fless]

And does the engine coolant temp sensor report accurately? Usually when they fail the radiator fans are on all the time but at least rule out the sensor.

 

[GMswin13]

My buddy has a really nice scanner we’re gonna take a look. I do know one of the lines were cold no condensation nothing puddles. Haven’t checked the other line.
Back in the winter the thermosdat was bad causing the coolant fans to run on high constantly so I changed that and the temp sensor and fixed the issue. So I’m gonna have to runt some codes I suppose and proper equipment to test the Freon

 

[Doubeleive]

My buddy has a really nice scanner we’re gonna take a look. I do know one of the lines were cold no condensation nothing puddles. Haven’t checked the other line.
Back in the winter the thermosdat was bad causing the coolant fans to run on high constantly so I changed that and the temp sensor and fixed the issue. So I’m gonna have to runt some codes I suppose and proper equipment to test the Freon

A scanner should be able to command the system on and show if there is any electronic problem, you might want to do a.little YouTube 101 on what the sensors should normally read. There was one guy on here who was a pretty good hvac wizz but haven't seen him post anything in a while

 

[BattleTank]

I wouldn't trust the gauge on the can. PERIOD.

Get yourself a decent set of gauges. Verify the compressor is even turning on.

Don't get caught dumping freon in the atmosphere.

 

[GMswin13]

Well I took it to my buddies shop put his ac gauges on it it’s full and correct where it needs to be.. a code was up for radiator coolant control sensor was reading 33 degrees. I’m not sure if this particular vehicle has more than one temp control sensors cause I changed the one that’s next to the thermostat housing 3 times already but that one is called coolant temp control sensor. And the fans aren’t working properly but I can’t find anywhere that the fans have a coolant fan control module or not?

 

[Fless]

I hope you're using OE GM parts -- from a reputable source -- since aftermarket parts aren't always as reliable.

If you could monitor that sensor that reads 33° (is that F or C?) with a scanner, unplug it (the one you replaced before) to see if the temp reading changes. That should be a two-pin connector so you could short the pins to see if the scanner reading changes.