Wierd hissing noise coming from the AC controls
#1
Wierd hissing noise coming from the AC controls
My 2002 blazer has a strange hissing noise coming from the vicinity of the AC controls when I turn the AC on. I turned off the AC and the hissing faintly continued so I started pressing around different places, found a sweet spot, pressed on it and the hissing stopped. I turned on the AC and the hissing eventually started back so I pressed on the spot and it continued at a lower tone and my AC started to blow harder. Is my AC switch faulty or does anybody know if there is anything that can be knocked loose back there? It's not something that inhibits the functionality of the vehicle but it annoys me and I want to fix it, any ideas would be appreciated.
#2
Where was the sweet spot as you mentioned. My guess would be a vacuum leak in the dash somewhere, I'm not sure what the controls look like on the auto climate systems but I'm guessing that vacuum is if not part of the switch it is close by.
#3
I have the manual operation AC, I found a thread that showed the back of the HVAC controls and there are quite a few vac connections to it. When I press the Vent Selection Dial on the far right or right next to it on the right side it quietens the hissing down and get rid of it when I turn the AC off. So I'm guessing I am going to have to dig around behind that area to check for leaks. What are the chances of the hole HVAC unit being defective?
#4
I have the manual operation AC, I found a thread that showed the back of the HVAC controls and there are quite a few vac connections to it. When I press the Vent Selection Dial on the far right or right next to it on the right side it quietens the hissing down and get rid of it when I turn the AC off. So I'm guessing I am going to have to dig around behind that area to check for leaks. What are the chances of the hole HVAC unit being defective?
#6
Nvm, found it on Amazon for 58 bucks. Here is the link for anyone else who needs it. Amazon.com: ACDelco 15-72883 Heater and Air Conditioner Control Assembly: Automotive
#7
Nvm, found it on Amazon for 58 bucks. Here is the link for anyone else who needs it. Amazon.com: ACDelco 15-72883 Heater and Air Conditioner Control Assembly: Automotive
#8
Thanks for the link. I see the GM switches are a lot like in the 70s. A vacuum cluster on rear of switch. Same as back in the 70s. I wasn't sure if that had changed or not. Now I know thanks. The big difference I'm sure is when they leaked back in the day you could take the vacuum port apart & re-silicone it & fix it.
Last edited by 4x4blazerguy; 05-11-2012 at 11:20 PM.
#9
don't mean to hijack your thread, new here! just got my first blazer wednesday! 1998, 4dr here. anyway, my ac controls don't change panels.... theres no hissing or anything. just blows at the feet, face, and defroster. any idea what it could be?? thanks!!!
#10
sounds like you have a vacuum delievery problem i would check you lines under the hood. make sure they arent spilt, cracked or rotted.