Went by the dealer again today. The source of the noise in my truck is in the evaporator housing that sits under the dash / behind the glove box.

The service manager thinks it is a vacuum line that is leaking - we'll see. Truck goes in Thursday for work.

The saga continues...

 

Thanks for the update. I haven't heard that one yet from anyone who has looked at mine. How long are they planning to keep your truck in the shop?

I'm looking forward to hear what they find. Thanks for keeping me updated.

 

UPDATE: Took the truck in and the service tech took the evaporator/fan housing apart that sits under the dash/behind the glove box. This is definitely the source of the "hissing."

He couldn't find anything and said he couldn't reproduce the noise. I figure I have 32,000 miles left on the warranty - it'll either get better ot get worse!

So, for now, I'm driving a $43,000 truck that is exceptionally well appointed, handles well, drives well, but "hisses" at me when the A/C is on... I saw a post on here trashing foreign trucks - bet they don't make a noise that can be heard over the radio when the A/C is on.

 

My 2004 also hissed when cycling on and off for the first ~6000 miles and then went away. The dealer I took it due thought it was an unloader valve cycling as the a/c would load. The truck now has 18k and the a/c has always worked like a champ.

 

Thanks. I hope it goes away - it sure is annoying.

 

My truck is making the same damn noise...I first thought it was my tape player, but upon investigation, I found that it was comming from the A/C unit behind the dash...I need an oil change, so I will get the stealership to take a look at that as well as my steering wheel shimmy and the poor acceleration.

 

Any updated info you get from the dealership would be appreciated. Mine seems to have good days and bad days. It must have something to do with the weather.

 

Good luck at the dealership - I took the service manager for a ride in mine and he could not hear the noise. I resigned myself to putting up with it. I'm well past the 6,000 mile mark (as another poster suggested) and the noise is still there. Clearly a bad design, but it still blows cold air (for now).