Engine whine (especially when revving up) & low voltage meter

Where are you getting your readings from? The alternator runs directly to the Fuse Box.

 

Do you have the Service Repair Manual?

 

By chance is the oil pressure gauge reading normal?

 

Try this-

1-hook up voltage tester to battery.
2-start truck, you should have 13.3v or more.
3-turn on lights radio etc., you should have 13.3v or more.

If not, your alternator is probably bad, it will show increase voltage with revs bad or not up to when the voltage regulator cuts off 14.5v ish.

Does your whine sound like this? A bad diode in an alternator can whine. Check out this video.

 

You can access the alternator connector through the passenger panel (point to access the alternator), Pink is where the clips, Red is the positive cable to the fuse regulator, Blue is the alternator connector that runs all the way up to the side of the fuse panel.

 

That would be my guess, too, but I don't even know where to begin searching for that connection. I think I'm just going to slowly clean every single exposed connection/ground I can find in the engine bay over the course of the week.

I'm plugging the volt reader directly to the positive and negative terminals on the battery. So since the alternator runs to the fuse box and then to the battery (hence the alternate fuse) and I'm getting a "charge" reading, I think that means the alternator is working good.

Unfortunately, no; got a link to one online?

I don't recall off the top of my head. I'll check in a bit.

I'll try those steps in a few minutes. No, the alternator doesn't sound like that at all. I stuck my head around the bottom of the engine bay and the top and am almost 100% sure it's one of the idler pulleys (used both a stethoscope near them and the tube trick).

Going to be a little more annoying getting to it from the side because my remote reserviors are mounted there. I took a look underneath and I think I have enough space there.

 

@joeguam, nope, the oil reading looks good; here's a video of the whole instrument cluster panel as I cycle from engine off to on..

https://www.youtube.com/watch?v=_iC9-bf_7IQ

@Vizsla, these are the readings without revving the engine..

 

Tech Stream (TS) has the ability to check the sweep of the individual gauges in 1/4 increments. Take the fuel gauge as an example, TS can make the gauge display 0/4, 1/4, 2/4, 3/4, and 4/4. This can be done for each analog gauge including the voltmeter. Going through these checks may indicate or eliminate the gauge itself. Of course you'll need someone with TS. All I can think of.....

 

That's perfect, would not waste anymore time on your charging system, but the 13v and 12v from your first results indicates trouble? I went out and checked my gauges, my volt gauge never goes below the 9, on-off same. Maybe gauge is bad.

 

I may have to drop by the dealership and ask them to do this diagnostic for me.. if it's not expensive.

I think with the first "results" picture I posted of the voltage reader was with me using the "load" feature on the tester, which probably puts more drain/stress on the alternator/battery than with all my electrical components all. This is the exact meter I was using:

$44 Schumacher Electric 100A Car Battery Load Tester and Voltmeter, for 6V/12V Batteries Up to 1000 Cranking Amps, Charging System Diagnosis, BT-100, for Power Sport, Automotive, and Marine Batteries

https://www.amazon.com/Schumacher-BT-100-Battery-Load-Tester/dp/B000AMBOI0/

 

Spvrtan
just noticed this, you asked me if:
"Is the AC compressor located near the belt? Because that's where I'm hearing the sound."

what i said about the compressor noise happened to my 2005 Tuscon after 187K miles ... ac still worked perfectly but made a whining noise.
i assume it can happen to any car so I was giving you some ideas.
It has a serp belt and the compressor was in the loop (if that's what you mean by "located near the belt")
I used a shorter belt and took the compressor out of the loop and it stopped the whining noise.
Not a real fix but I have 3 other cars and don't need the ac on that car. It may have worked like that for few more years or days but didn't want to risk it. any noise or leak and I am on top of it quickly.

 

Update for this thread in case anyone else comes along with this problem, too..

It turned out my supercharger idler pulley's bearing was in fact dried out from getting degreaser in there. I swapped out the pulley, which is the same as the one used for the tensioner, and did a write up on how to do it yourself here:
https://www.tundras.com/threads/diy...rpentine-timing-belt-and-idler-pulleys.12189/