Mazda3- Constant high pitched noise

[LTC8K6]

hm.. where exactly do I put the leds of the voltage meter to test alternator?

Set it for DC volts and check the voltage at the battery terminals with the engine running.
If you do the test, report back with the voltage.

You can go through Tortillasoup's rigamarole if you want.

I wouldn't bother with all that. :biggrin:

 

[tortillasoup]

Set it for DC volts and check the voltage at the battery terminals with the engine running.
If you do the test, report back with the voltage.

You can go through Tortillasoup's rigamarole if you want.

I wouldn't bother with all that. :biggrin:

Yes well op has a specific problem and if you just do a simple test like you suggest, you'll miss out on a lot of problems. I had a guy come to me who had his alternator replaced 4 times and battery 2 times! He stopped going to his previous, "trusted" mechanic because there was a death in that mechanic's family and his life fell apart, and could no longer work... Anyway that "trusted mechanic" hadn't bothered to look at the Fuse box that sits on top of the battery (Volkswagen Jetta) where he would have discovered it had melted and corroded terminals. This, coupled with poor electrical grounds in the engine bay was the reason for his charging issues. I did all the testing prior to digging into the problem.

 

[LTC8K6]

We need to start simple with the OP.

If simple indicates a problem, then we can go deeper.

 

[tortillasoup]

We need to start simple with the OP.

If simple indicates a problem, then we can go deeper.

And if OP doesn't do a thorough checking, he could miss a problem. I've seen lots of cars do excellent charging voltage only to sag to battery voltage when put into drive or when the highbeams turned on, etc.

 

[HitAnyKey]

I second the suggestion to unplug all accessories and audio cables if connected. Those can definitely cause a whine sound.

Funny thing. The only thing to fail on my 04 (owned it for 7 years) was an Alternator. So that is a good guess. But do the proper checks to make sure your not chasing a ghost. Pun intended

And by the way, if you have never done an Alternator before find a good mechanic to do it or walk you through it. You don't want to get stranded in a snow storm because you didn't install it properly and your battery discharged

 

[LTC8K6]

And if OP doesn't do a thorough checking, he could miss a problem. I've seen lots of cars do excellent charging voltage only to sag to battery voltage when put into drive or when the highbeams turned on, etc.

First, let's see if he gets started on checking the voltage. :biggrin: