Hissing Noise from Dash

[CdnCutlass]

Hey guys,

When I adjust the climate controls in my car there is a strange hissing noise coming from the dash if the temperature is not all the way over to the coldest setting. It doesn't matter what the other setting is whether its a/c, vent, heat, defrost etc. Seems to be related to the temp setting. Does anyone know what would cause this?

 

[wonderboy24]

could be a vaccum line to your controls. either loose or has a pin hole in it. or could be a prob with the damper door.

 

[CWPottenger]

Hey guys,

When I adjust the climate controls in my car there is a strange hissing noise coming from the dash if the temperature is not all the way over to the coldest setting. It doesn't matter what the other setting is whether its a/c, vent, heat, defrost etc. Seems to be related to the temp setting. Does anyone know what would cause this?

There is a vacuum manifold on the back of your climate control that sends vacuum to all the doors on the heat and AC system. Most likely one of the lines is off or cracked, also possible the vacuum block connector is off the tabs allowing a leak.

 

[tetomas]

Most likely need a new vacuum block valve on the back of the climate control head.

 

[CdnCutlass]

Thanks for the fast replies. I will pull the controls and have a look behind. It sounds like a vacuum leak, but wasn't sure.

 

[procircuit]

It's a snake be careful!

 

[G-Body_Vet]

You can spray down the vacuum lines with soapy water to find leaks. Avoid anything electrical obviously.

 

[tc1959]

Vacuum select switch on the back of the control panel $ 23.79 at http://www.rockauto.com ACDELCO Part # 1571389

 

[CdnCutlass]

This is where I found the noise to be coming from. Has two vacuum lines going to it, vacuum is re-directed when you move from cold to hot. Does anyone know what it's called and where I could get one?

 

[CdnCutlass]

After some research it turns out 4 Seasons makes a replacement part. Going to try and order this tomorrow.

Part Number: 36693
Vacuum Mode Selector Switch