strange noise!

[cmills]

When the truck is off and the doors are shut there is a slight humming or buzzing noise that I can hear when I put my ear right down in front of the 8.4 inch touch screen. It stops as soon as I open the door and the lights come on and the dash lights come on. when I shut the door and the lights go off and and the dash lights go off it starts again probably within a minute. It doesn't matter if it has been sitting for an hour or 5 hrs it still does it. Could somone see if theirs does the same thing? Thanks

 

[JLandry]

My guess is it's some sort of proximity sensor. For what purpose I don't know.

When it's quiet enough, I can occasionally hear something similar coming from my iPhone 5.

John L.

 

[Powder Extreme]

Yup mine does it too. My Gmc does as well. There is always something going on even though the key is off. My 1/2 ton is really bad. 10 minutes after shutting the truck off, the air suspension might adjust itself. That freaked me out late one night in my dead silent shop.

 

[Dieselnerd]

Funny this should come up today. I've never noticed any noises but yesterday my wife was waiting for me in our truck and she asked me what was running in the truck. She said it started and stopped a few times. This was with the ignition off although the truck is keyless and she has a fob in her purse.

My wise guy answer was that these new trucks are alive and something is always going on unless the batteries are disconnected. I was half joking but with all the computer stuff, I'm sure it never sleeps. Probably talking to the NSA for all I know.

 

[SSchang]

Could be the CD/DVD player spinning?

 

[Powder Extreme]

My 1 ton does it and it doesn't have a CD player. And it comes from the dash anyway. The cd is mounted under the armrest in the console. I'm guessing part of it is HVAC door motors for some silly *** reason. It's definitely a motor of some sort running.

 

[Darmeisner]

My 3500 does it also...except it sounds like there are 2 or 3 motors running at different times. It's definitely under the dash cause that's where my head was looking for the brake controller plug. Didn't find it

 

[cmills]

Well this makes me feel better that it's not just mine.

 

[sag2]

After you shut off any new vehicle today there are all kinds of behind the scenes housekeeping going on. On LX cars the A/C doors all cycle through their travel about a minute or two after shut down. Your turbo also makes a sweep on key off, and a bunch of other modules go through a shut down routine. Kind of like shutting down your computer.

 

[JLandry]

After you shut off any new vehicle today there are all kinds of behind the scenes housekeeping going on.

The 2014 Owner's Manual states in two different places:

The DEF pump will run for a period of time after engine shutdown to purge the DEF system. This is normal operation.

Not sure where that's heard.

John L.

 

[mpaulson]

In the knee bolster right where your right knee would be, you will see a little 1" x 1" area that the plastic has little vent slots, there is a little fan in there that for whatever reason moves air through the little vent and if the ignition is in the accessory position or you haven't opened the door after shutting the truck off, is is still buzzing away. This maybe what you are hearing.

 

[cmills]

I guess I don't know if it is doing it 24hrs a day when it's just sitting there but I do know that I went and checked it after it had been sitting for several hrs and it was doing it. Now maybe when I open the doors and the dome light and dash lights come it restarts something and makes it do it again. I really don't feel like sitting in the truck for hrs to see if it stops, whether after 20 min or 8hrs or if it ever does.

 

[JLandry]

...you will see a little 1" x 1" area that the plastic has little vent slots, there is a little fan in there that for whatever reason moves air through the little vent...

Fart fan?

John L.

 

[jus2shy]

That buzzing noise is probably the duct on top of the HVAC module. It switches from fresh air intake to in-cabin recycling. If you take out your glove box and look up, you'll see a white "Dryer-vent" like hose on top of the HVAC module. If you start your truck and then stop it, you will see this hose dis-engage from the top of your HVAC module. I think it's a slick setup for how RAM handles in-cabin recycling.

This freaked me out while I was installing the in-cabin air filter kit. I start cutting at the box and this weird buzzing noise starts. Glad to see the mechanisms were just moving around doing their "Thing".

 

[Powder Extreme]

I'm guessing that might be an inside air temp sensor. My '03 GMCs had a little vent with a fan in it inside the headliner right above my ear. Sometimes that thing was annoying as hell.

 

[JLandry]

...while I was installing the in-cabin air filter kit.

Can you believe a $60,000 truck doesn't come from the factory with a cabin air filter?

What's even more amazing is the HVAC housing is ready for it and all it takes is a hole, a filter, and a snap-on cover.

I wonder what rationale could be behind this omission?

Anyway, I've got a cabin air filter kit on order...

John L.