I wanted to revisit a post made here a few months ago. I have an '05 Super Cab Lariat that works flawlessly (except for the A/C). There is a hissing sound that seems to cycle every 10-15 seconds while the A/C is running. The sound is coming from behind the glove box. Anyone else run into this, or have an idea on a solution.

 

I had a Dodge truch that would do that. It turned out to be what I will call a vacuum actuator leaking. The "actuator" used vacuum to open/close a gate or door inside the assembly. The actuator would bleed down, due to a leak and the system would sense it was closed and reopen it. This "may" be wghat you have. Hope this helps.

 

Probably the refrigerant swooshing around. Mine does it too. If it's cooling good, I wouldn't worry about it.

 

I just bought an '05 Lariat and are having the same problem with the A/C. That constant hissing sound every 10 seconds is annoying the hell out of me. I'm going to take it back to the dealer and see what they say. I'll let you know as soon as I find what is wrong with it.

 

Thanks for the feedback. Mezmerize, let me know what you find out.

 

I have the same problem too. I don't know what it is though.

 

I have an appointment on Thursday to take my truck in to get that noise checked out along with a couple of other things that needs to be done. I will update you on what they say.

 

I have an 05 flareside scab and mine does it too.

Let me know what the dealer says Mez pelase.

Thanks bud!

 

Okay, so when I took the truck in for service on Thursday, of course, for some reason or other, the A/C was not making the noise no matter what I did. Its always like that, as soon as you want to take it in for something, it always seems to be working just fine until you bring it back home. Anyway, I explained to the service manager the noise as best I could. Seemed like he knew what I was talking about, said it was normal but they were going to look into it. Picked up the truck today (Friday) and they said they pressure tested the A/C, and everything checked out. They said the noise I was hearing was "normal cycling noise from the evaporator". So I guess everything works out and the only solution to the annoying noise is just to tune it out with the radio. Hope this info helps you guys. If you hear anything different, please let me know.

 

Thanks Mez for letting us know.