Question for auto mechanic..need help

[jimdana1942]

2006 Chev. Trailblazer...alternator is making a noticeable whining noise that increases with RPM, not the kind of noise a dry bearing makes but more of a buzzing noise.

Drivers door power windows and door lock switches not working. Passenger door and rear door switches work fine but lost control from the drivers door panel.. Have had fuses checked, told they were okay.

What to do?

 

[firesafety3]

My wife's Trailblazer did the same thing. Bought an idler pulley from AutoZone and changed it out in about 15 minutes. It would help to have somebody there to help route the belt back on.

 

[Storm52]

Could be idler pulley, which emits the whine and is near the alternator. The window/door lock switches may be toast if excessive amount of rain got in there. Pull the door panel off and check the connections. Hard to imagine them pulling loose, but it may have happened. Get to a U-Pull-It salvage type yard and get a replacement switch panel. Hook up (before installing) and see if that fixes the problem. All else fails, mechanics make their living repairing Chevys.

 

[d_hawkins]

I worked as a tech at a Chevy dealership for 4 year, i cannot tell you how many trailblazer idler pulleys i replaced. I could hear them pulling in the parking lot. warranty paid good and it took 10min lol. i would start there.

 

[jimdana1942]

The idler pulley on this one is on the lower part of the engine on passenger side and the alt. is on drivers side of engine. We listened best we could and it seems loudest at the alternator best we could tell. Alt. looks like it would be difficult to take off as lower bolt seems in a bad location. I was thinking maybe if we could slip belt off idler pulley how can we be sure the pulley is the whiner?

 

[firesafety3]

Idler pulley is on the right (driver's side), second from the top, the smooth surfaced and about 3.5"in diameter. No need to remove the alternator.

Your tensioner pulley will be bottom left. Ya gotta feel around to get the 3/8" drive in it, push it hard to the right, and remove the belt. Watch your fingers...that SOB will bite you. Wear some gloves, this is a knuckle busting procedure.

An old trick to find the "whiner", cut about 3 feet of garden hose and put it to your ear then in front of each pulley.

 

[LNSvince]

not the kind of noise a dry bearing makes but more of a buzzing noise.

Assuming you are accurate in knowing what a bearing noise sounds like. with the engine off, Disconnect the alternator wiring harness plug on back of the alternator [ NOT the battery cable to the alternator ]
STart the engine, the alternator should not be charging.
Is your buzzing noise the same or different.
With the engine running, plug the harness back in. The alternator will begin to work. Does the noise change.
This is 1 informal check you can do to help determine if its the alternator or a pulley.
Pulley bearing noises will throw you off. Whether its an Idler pulley, or the actual pivot point in the tensioner.
Both are common. If your NOT sure, DONT GUESS. Its OK to have a professional look at it.
You also have an electronically controlled fan clutch, that is a potential source of noise.

Next, for everyone else.......... NEVER take the battery cable off of an alternator or an actual battery cable , to check your charging system the "OLD SCHOOL" way.
No need for any explanation - JUST DONT DO IT ! Because I said not to.

Next, if you need to replace the Alternator, PLUH-EASE purchase a quality part. IN your case a Delco or Delphi.
There is a Difference in the quality of electronics.
Yes any aftermarket alternator will charge the battery. But only a good alternator has the quality parts to filter out the AC noise and other unwanted spikes a generator will create.
I could show you on a lab scope why you don't want a cheap alternator.'
However like my last comment, TRUST ME, Don't buy a cheap alternator.


All vehicles are now using multiple computers [ modules ] and all are connected by 2 serial data bus wires.
the Adaptive strategy's of the multiple modules can be seriously effected by this "noise".
A little corrosion or bad connection will begin to store "bad" corrections and alter the way your car runs.
It takes weeks sometimes, and you never notice it.

If you take me a quality video of the noise, you can email it to me.
I might be able to help you. vince@LNSauto.com

If you were close to my shop, You could come by and Id look at it for you.
Things that are simple to look at, I don't charge you. Its just part of being a good business person.

An old trick to find the "whiner", cut about 3 feet of garden hose and put it to your ear then in front of each pulley.

this is a good one too.