Mopardik

Well, so far I love my new (to me) rig. Thanks to those on here for much info and opinions before my purchase. I'm starting to work my way through everything on it to see what I've really got now, and came across something kind of odd. There is a buzzing in the dash around the HVAC cluster that sounds kind of like a small motor running. It comes on for 3-4 sec. every 15 sec. or so. It is enough of a draw to dim the cab lights slightly when it does. It does it with the HVAC controls on or off, doesn't matter. If it's normal then I'm fine with it, but I'm just curious what's going on back there. Any ideas?

Lost Lake

Where do you live Mopardik? Is it the grid heater cycling?

Mopardik

I really don't know. I am not new to Dodge trucks, but definitely new to the diesels. I had an 05 1500 that never made this sound. I'm learning more every day and although I've heard of the grid heater, I have no idea where it is. I live just outside of STL, MO and it's about 25 here right now.

1-2-3

My 04 does this and I cannot find the source. It's not grid heaters. It's inside the dash somewhere.

cbrahs

do me a favor. when driving and you hear this noise. click the tow/haul button. does it get louder? also push down on the gear shift lever a bit. DO NOT change gears but just push it down to where it stops while in drive. DO NOT GO INTO 2nd GEAR. Mine has been doing the same thing since new, dealer can't figure it out. I can make it louder with tow/haul button on or off. sounds like a stepper motor behind the cluster area but there are no stepper motors.

Mopardik

Yeah, it's definitely inside the dash somewhere right around the center cluster. BTW, it does it whenever the key is on, it doesn't even have to be running. I paid a little closer attention to it, and it's kind of a 2 stage thing. It's an electrical load first (dash lgts. dim slightly), and then a second or 2 later the buzzing starts (like a relay is triggering it).The stepper motor thing is spot on for the type of sound. I'm glad to hear that it's happening to others, and not an issue that requires prompt repair or anything. I will try those things tomorrow to see what happens, and let you know. Thanks guys.

cbrahs

mine only happens when driving. the techs have torn the entire thing apart and when it was new, they replaced the cluster just cause they were stumped as to what it could be. let us know what you find.

Jeff in TD

What year is your truck?

The earlier 3rd gens have the lift pump mounted on the fuel filter. You will hear it cycle on and off when you turn the key on, and it will cycle as needed to maintain pressure.

Also, on 2003's there was a TSB regarding replacing the pressure line from the power steering pump to the hydrobooster with a revised hose that has a metal crimp, and a large weight mid-span. It cures a vibration in the pedals/wheel at 2000 RPM.

My 03 had this, and it sounded like someone was playing a kazoo in the dash.

1-2-3

Mine that's doing it is an 04.0. It's not the LP. I've already verified that.

Bone

I had a small hose break twice on me, when it did it made the humming noise whenever the key was on. If its an auto look by the tranny fluid dipstick(firewall) and you'll see a small 1/8 in dia hose. Seems like it might be the windshield washer fluid pump running. Like I say I've had the line break twice, used some rubber connectors from autozone to fix it. Once you fix the air leak the humming goes away.

Jeff in TD

The autos have an electric vacuum pump, which have been known to get buzzy...

1-2-3

I've heard of a vac pump near the passenger battery. that's too far away to be this. Where is the mentioned electric vac pump located? And it's not a busted w/w hose. My hose aint busted and it's doing it.