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Discussion Starter · #1 ·
A couple days ago I noticed that when I started my car, even cold, the secondary cooling fan kicks on.

Then I noticed when I turn the AC on, the orange light on in the middle of the knob just flashes a few times then goes off.

I know the secondary fan is connected to the AC in that it goes on when the AC is on in addition to just when the engine hits max temp.

Could I have an electrical gremlin? Anyone else had these issues? What should I look for?

Thanks!

Alex
 

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Just checking first... but it isn't 40 degrees or lower there is it?
 

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Discussion Starter · #3 ·
Nvr2loud said:
Just checking first... but it isn't 40 degrees or lower there is it?
Yeah, the high on Saturday is still only going to be 34C. That's still plenty hot enough to need AC, especially with an all black interior made of plastic lol.
 

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From Section 8 page 2 of the 2014 Acadia Users Manual:

(Air Conditioning): Press to turn the air conditioning system on or off. An indicator light comes on when A/C is on. The air conditioning
system does not operate when the outside temperature is below 4°C (40°F). The indicator light flashes three times and turns off when
outside conditions affect air conditioning operation. This is normal.
 

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Discussion Starter · #5 ·
golf2beach said:
From Section 8 page 2 of the 2014 Acadia Users Manual:

(Air Conditioning): Press to turn the air conditioning system on or off. An indicator light comes on when A/C is on. The air conditioning
system does not operate when the outside temperature is below 4°C (40°F). The indicator light flashes three times and turns off when
outside conditions affect air conditioning operation. This is normal.
I fail to see how this pertains to me? Are you saying it's for sure an electrical bug since it thinks it's too cold outside? How would that affect the secondary fan being on, or is that an unrelated bug you think? They both started at the same time.

Anyone have a wiring diagram of where this mystery AC outside temp sensor is? It can't be the same a the dash since that's working correctly.

Also where is the sensor that controls the secondary fan (I know one is coolant temp)? Are these perhaps on a fuse together that is blown?
 

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Also where is the sensor that controls the secondary fan (I know one is coolant temp)? Are these perhaps on a fuse together that is blown?
The fans are controlled by the Engine Control Module that gets its input from many sensors and control modules based on heat load on the engine and A/C use. One outside air temp sensor is located in front of the condenser and radiator. There are two fans and they can operate at low and high speeds as required. There are three relays that control the fans located in the fuse panel under the hood. There is also a fuse for the fans in that panel. You may want to check those.

GM has had the low temp(40F) shut off feature for the compressor since at least the early 60's. It is to protect the type compressor they use.

One reason the system is not working could be low refrigerant. That would be an easy fix but it could be a bad control module or stuck relay.
 

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Discussion Starter · #7 ·
Thanks for the info.

If it were low on refrigerant then perhaps the low pressure switch will cause that orange light. The AC was working perfectly though right up until that prior day, I was using it the day before. I'd expect if it was low, it would cycle on and off and not get cold, unless of course it was a catastrophic leak.

I'll check the fuses and relays you mentioned. It really is odd to me that both my fan and AC began malfunctioning at exactly the same time so I can't help but think the malfunctions are linked...
 

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Discussion Starter · #8 ·
So, interesting. Removing the ECU fuse and putting it back makes it work great, nice and ice cold. Then after only a minute, it flashes and goes off again. WTF.

I can reproduce this over and over again. Any ideas?

Also just to be clear, I'm not running low on refrigerant. That's happened before and the AC still ran fine, just at a warmer temp. I had that fixed under warranty a couple years ago. At least now when it does work, it blows ice cold so I can rule that out.

It did occur to me, that this started happening after the last time I cleaned my engine. Perhaps moisture go somewhere it shouldn't have under the hood? Any idea which connectors I should pull apart and check?
 
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