AC not working

Tiny
514
  • MEMBER
  • 2011 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
AC does not work. Compressor does not engage. Shop says the relay is good. That is as far as they got. They suggested that the wire is shorted somewhere between the Low pressure switch and the relay. The shop does not have a good electrical guy so they source this type of stuff out.

I decided to try myself if I can find the time.
Does this sound right or should I be checking the wires replacing/testing the switch?
Or looking elsewhere?
Anyone know how?
Do you
have the same problem?
Yes
No
Friday, March 31st, 2017 AT 10:17 AM

26 Replies

Tiny
CARADIODOC
  • EXPERT
First you have to determine why the compressor is not engaging before you will know what to look for. All AC systems have some means of disabling the compressor if the system pressure gets too low. If there is a big enough leak, the compressor could put the system into a vacuum, and that could draw in outside air. The humidity in that air combines with refrigerant to form an acid that will attack metal parts. Once the system is recharged, that moisture will circulate and freeze at the orifice tube or expansion valve. That ice will stop the flow of refrigerant until it melts. That typically causes intermittent loss of cooling that can last up to an hour.

There is a low-pressure cut-off switch or a pressure sensor that disables the compressor. The place to start is by measuring the system pressure. If it is low, you will need to search for a leak, then recover the refrigerant that is left in the system, then recharge it with the amount specified.
Was this
answer
helpful?
Yes
No
Friday, March 31st, 2017 AT 3:11 PM
Tiny
SKINUT20
  • MEMBER
  • 2009 CHEVROLET SILVERADO
  • 4WD
  • AUTOMATIC
  • 110,000 MILES
With A/C on. Passenger side blows cold air, drivers side blows warm air. I found the actuator on the left side of the air box that was not working and replaced it. How do you set the disc that the actuator moves to open and close flaps in the air box? Right now it is still doing the same as before I replaced the actuator.
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:33 AM (Merged)
Tiny
HMAC300
  • EXPERT
Pull HVAC fuse inside truck for sixty seconds with key on then reinstall. It should reset of course it should have been lined up prior to install.
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:33 AM (Merged)
Tiny
TINAJOHNSON615
  • MEMBER
  • 2009 CHEVROLET SILVERADO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 85,000 MILES
Trucks been parked all day got in it cranked it and ac wouldn't come on. Said engine was too hot to run ac. But checked the engine and fluids all is good but it wont let the ac be turned on. What should I do?
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:33 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Is the temp gauge showing that it is overheating?
Was this
answer
helpful?
Yes
No
-1
Friday, June 26th, 2020 AT 11:33 AM (Merged)
Tiny
TINAJOHNSON615
  • MEMBER
He disconnected the battery cable and hooked it back up now its working fine. Think it was just the sensor acting up. Thanks
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:33 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
That is good news. Let me know if something goes wrong.

Joe
Was this
answer
helpful?
Yes
No
+1
Friday, June 26th, 2020 AT 11:33 AM (Merged)
Tiny
BRIAN RHINEHEIMER
  • MEMBER
  • 2007 CHEVROLET SILVERADO
  • 6.6L
  • V8
  • TURBO
  • 4WD
  • AUTOMATIC
  • 133,000 MILES
A/C fuse is dead on hot side. I put a fused wire in the fuse and hooked to positive post of battery. Air works fine, clutch engaged. Why would that fuse be dead? Relay is good.
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
CARADIODOC
  • EXPERT
There are multiple fuses in this system. If you can figure out which one is dead, I will figure out where it is fed from.

Fuse 40 is a 10-amp. Fuses 59, 62, and 72 are each a 40-amp. All of these are listed as "hot at all times", meaning there is nothing switching them on and off. Fuse 18 is a 10-amp and is only for the compressor clutch. That one gets twelve volts from the AC compressor relay. That relay is turned on by the engine computer unless the system is low on charge.
Was this
answer
helpful?
Yes
No
+1
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
BRIAN RHINEHEIMER
  • MEMBER
I will check that stuff out. Thanks for the information.
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
KEN
  • ADMIN
Hello,

I have found the wiring diagrams (below) for you so you can do some testing. Here is a guide that will help you check for power and ground triggers to see where the failure is happening.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Please run some tests and get back to us so we can continue helping you.

Cheers, Ken
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
NAVYGUY76
  • MEMBER
  • 2007 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 67,000 MILES
The air conditioner wont work. One day I pulled in and turned the engine off and the air kept going. I pulled the fuse and it turned off. Now I plugged the fuse back in and it worked for a few day and now it quit. I cant even get the heater to work. What can I do to fix the problem?
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
What fuse was removed? Is it the blower motor fuse?
Was this
answer
helpful?
Yes
No
-1
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
NAVYGUY76
  • MEMBER
Yes I removed the blower fuse. It was a 10 green fuse. Do you think my blower may have gone bad or do you think the wiring is bad? I am gonna try to replace the fuse today but I have doubts that is what it is.
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
It could be a few things. What I need you to do is check the blower motor (when not working) to see if there is power to it. If there is power, the motor is the problem. If no power is present, then I walk you backwards through the system. It's not as bad as you would think. The blower motor is under the dash on the passanger side of the vehicle.

Let me know what you find.

Joe
Was this
answer
helpful?
Yes
No
-1
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
HECTOR2025
  • MEMBER
  • 2007 CHEVROLET SILVERADO
  • 6 CYL
  • 2WD
  • 40,000 MILES
Hello, I have a 2007 Chevy Silverado and my problem is that my air air conditioner will work for a couple of days and then it will stop working. When it stops working the light on the ac button will turn on but no air flow comes out through the vents.
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
WRENCHTECH
  • MEMBER
That's the blower system that you're having a problem with. The next time it happens take a large screwdriver and hold it by the blade and give the motor a rap with the handle and see if it starts. If it does, replace the motor.
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
HECTOR2025
  • MEMBER
Thank you Wrenchtech I will try that.
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
2CARPROS-ARCHIVES
  • MEMBER
  • 2007 CHEVROLET SILVERADO
  • 36,000 MILES
When ac is turned on, it blows "hot" air. I pushed the compressor button in and it stays lit. I have the slide control all the way on blue for cold, nothing but hot hot air.
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:34 AM (Merged)
Tiny
HMAC300
  • EXPERT
Check freon level first it may be low if compressor is running then check actuator in heater as one controls temp, remove hvac fuse for 60 seconds then reinstall with key on. It may reset after a minute if not the actuator may not be working. Generic pic included.
Was this
answer
helpful?
Yes
No
Friday, June 26th, 2020 AT 11:34 AM (Merged)

Please login or register to post a reply.

Sponsored links