I have a 2000 trailblazer I keep getting a noise from the dash. when idling it is there when you tap on accel it seems to go away or you put trans in neutral it goes away. any ideas

 

Could you be more specific? What does the noise sound like? Where exactly is it coming from? Under the dash? On top of the dash? To the driver's side? Passenger's side? Does it sound like it's inside the truck or outside...

One thing that I have had to do on mine is add in a set of conical washers to the hood hinge bolts (GM has a TSB on this issue). Loose hood hinge bolts would make a sound very similar to a bad ball joint, but up at the base of the windsheild and to the outside. I suppose if they were real bad, the hood may not clunk, but the bolts may vibrate.

Have you made sure that it isn't something that is vibrating around inside of the ash tray or glove box?

Please let us know more so we can help to narrow this down for you.

 

It is coming from the drivers side spedo, tach area it sounds kind of like a gear rattling

 

There aren't any gears in the dash persay... It's possible that at some point your dash has been removed to service the heater core and things weren't put back together properly.

This definitly doesn't sound familiar to anything that I have seen on here...

You could pull off the hush panel from underneith the dash and have a listen again to try and narrow it down...

 

Thanks i will try that. would the speedo or tach make a sound similar? like it needs grease?

 

Nope, they're all electronic. No cables or gears.

 

DO the speedo and tach have gears in them that are driven by the electronic signal or a motorthat drives them. What is a good shop manual for this haynes?

 

No shop manual will dive into the gauge cluster. And No, I do not believe that the tach or speedo have gears that drive them. I believe they are a direct drive off of a precision electric encoder motor. Even if they had gears, the gears would be plastic and should not emit any should loose or not.

As far as a manual... I would HIGHLY recommend a factory service manual, but they are $$$. Helm Inc. sells the FSM for around $130. Every once in awhile you can catch them up on eBay. I have a Haynes and to be honest with you, I don't even know where it is at the moment. I use AllDataDIY.com as my primary resource. I have each one of my vehicles and all of my families vehicles that I work on under my account.

*EDIT* - looks like they're on sale for $67.50 for the 2000 model year set. I'm gonna have to grab this while I can!

 

i have a 2000 blazer that makes the same noise....sounds like a gear in the speedo running when idling....it drives me crazy....it has been doing it for years now....i have no idea what it is....i got tired of looking for the problem....if u find out what it is please let me know

 

If you guys really think it is the gauge cluster, it is fairly easy to remove. Disconnect the battery. Pull off the trim panel that extends down around the radio/climate control (it just clips in). Remove the screws holding the cluster in the dash. Pull the cluster out far enough to disconnect the wiring harness (may need to put the steering column in to full tilt down). Remove the cluster.

I haven't tried it, but I think you should be able to start the vehicle with the cluster out. So you'd need to hook the battery back up. Worst case is that it won't start and may store a code, but it shouldn't be anything that disconnecting the battery (when you put the cluster back in) wouldn't clear.