Buzzing under dash?

[Portedfrankenstien]

Not sure if this is the correct spot to post this. Recently I've noticed a strange buzzing, almost rapid clicking noise in my dash. Between the cluster, and climate controls. It happens at all times, and doesn't change with anything (headlights on/off. Blower on/off. Stereo on/off.) Assuming blend door, but I'm not having any problems with it. It almost sounds like when the blend doors go bad on the gmt800s. But every blend door I've fixed on an NBS, did that weird clunk noise, and then would go quiet for a bit. This noise never changes. Stays very consistent with no speed variation, and no volume change. It's my DD, so I can't tear it apart, and have it down for very long. And I don't get much time to work on my truck anymore, with working 60+ hours a week, and having my three year old daughter with me most nights. I've not heard of this issue on a gmt400 yet, so I'm curious if anyone has dealt with it, and can give me an idea, before I tear it down, and make it undrivable.

 

[east302]

Does it make the sound if you're stopped?

If it's up high (say behind the airbag or cargo lamp switches?) then I think that you can rule out a blend door. The hvac box is down at the floor, look up next to the gas pedal and you'll see an actuator and linkages. The other actuator is at the center bottom of the dash (maybe behind the ashtray?) and the recirculation actuator is over at the passenger side.

I know it's a common issue on the next generation, but wonder if it's a stepper motor in the gauges.

Last, is your trip odometer stuck trying to turn over the 9/10 digit? That can make an annoying clicking sound.

 

[Portedfrankenstien]

The tripometer isn't stuck, because it's the only way I can tell how much gas I have. The stepper motor for the fuel gauge is bad. I actually pulled the cluster apart awhile ago, and cut the needle off because it kept jamming itself behind my oil pressure gauge, and I couldn't see how much oil pressure I had. But it never made that noise before I cut the needle off, and didn't start for awhile after. I suppose it could have just gotten worse. It just sounds like its deeper in there. Nothing else changed, and nothing stopped working. It happens driving, or parked, and even happens KOEO. I haven't leaned under the dash to listen at all, because I haven't really been super worried about it considering nothing else is different yet, except the noise

 

[df2x4]

The stepper motor for the fuel gauge is bad. I actually pulled the cluster apart awhile ago, and cut the needle off because it kept jamming itself behind my oil pressure gauge, and I couldn't see how much oil pressure I had.

Well that's a little extreme, the needles can just pull straight off with a fork or similar pry tool.

 

[Portedfrankenstien]

Yeah, that's what I had originally done, but I didn't like the way the hole looked without it, and the way the light shone through it at night. Although it is now missing the needle, it really looked like it was missing something without the cover on the hole. I'm obsessive compulsive over missing parts, and pieces. I would have just grabbed another cluster, the last time I was at the yard, but I'm already on my third try for clusters in my truck. Original one, the needle stayed pegged. Second one, the needle would say it was half full on one drive cycle, and full on the next. Second one also had a tripometer that no longer worked, so I really needed to get away from that one. And the third (present), the needle danced around like a crack head on pay day, and would flip around so hard it would jam under the oil pressure needle, causing me to have to pull it apart to get it unstuck. After four times of doing that, I finally just cut it with a pair of *****, and put black paint over where the needle came out.

 

[df2x4]

Ah, I didn't even think about the light shining out when it was illuminated. That makes sense. Sucks you've had such bad luck with clusters, makes me feel lucky that both of my factory clusters haven't developed any problems. (Knock on wood...)

 

[Portedfrankenstien]

Ah, I didn't even think about the light shining out when it was illuminated. That makes sense. Sucks you've had such bad luck with clusters, makes me feel lucky that both of my factory clusters haven't developed any problems. (Knock on wood...)

Yeah, it's been really frustrating. The previous owner was convinced it was just a bad sending unit, so he replaced the entire pump assembly with a new Delphi pump like 4 months before I bought the truck. So that's a plus side to that ty situation, the pump is only a little more than a year old. Ha ha. Plus, since I know the previous owner because he is a coworker, and I'm friends with his son, it has a lifetime warranty. So long as I keep contact with them when/if the pump goes bad. The real irritating part is, I know it's the cluster, because my girls little brother has a 95 k1500, and I swapped with him awhile back, for about a week, and his cluster works perfectly. Envy is a *****, sometimes! Ha ha

 

[GT_80]

wonder if you have a bad ground on your fuel sender... It would cause the gauge to do all kinds of wacky stuff. changing the gauge won't fix that either.

 

[Portedfrankenstien]

wonder if you have a bad ground on your fuel sender... It would cause the gauge to do all kinds of wacky stuff. changing the gauge won't fix that either.

Well, I might think that also, if I hadn't switched with my girlfriends brothers 95. His cluster was in my truck for about a week, and worked awesome. No issues at all. And I probably put a good 200+ miles on it that week, intentionally. If it wasn't for that one cluster operating properly, I might still consider the possibility of it not being a stepper motor. In fact, I may even have decided that it was indefinitely something else. But like I said, I just cut the needle off, and gave up on worrying about the fuel gauge issue all together. I rely solely on the tripometer now for fuel level purposes. 300 miles is right where I consider it to be empty, and need to get to a gas station. It's pretty accurate with about 5-7 gallons of fuel to spare. This typically keeps me out of trouble, too, because I don't push it until it's past empty on the gauge. I'm well known for pushing my vehicles past empty. Not from having no money, but rather pure laziness to go fill up. Ha ha. Yes, I've pulled the tank out of plenty of my vehicles in the past, because I've burned up pumps. I'm ignorant when it comes to certain things. I change fluids prematurely, because I'm **** about maintenance. But I'll burn up a fuel pump out of neglect, simply because I don't want to go to the gas station. Ha ha