2003 GMC Yukon 5.3L voltage gauge goes high then down

[Summajet]

5.3L V8 engine. Cranks/starts up fine. I noticed driving home last night that the volt meter would rise to about 14.5-15 volts and then down to about 14 volts.
I replaced the alternator belt last November when rebuilding the motor.
Alternator was new and installed in Jan. of 2016.
I noticed as the volt gauge moves that the headlights and gauge flickers for a second.

Here is where I will start to check,
1. check battery terminals for corrosion.
2. fan belt
3. loose connections on wiring harness to alternator.
4. check battery to ensure it is not weak or failing.

Wondering if the voltage regulator is going bad in the alternator?

Has anyone experienced these similar issues and if so what was the issue and fix?
Thanks,

 

[Big Mama]

Check the ground cables all around. This happened on my boat which is a 5.7. The voltage went up and it kicked my amp off but if I used an accessory that needed power, like my trim, it would go back down. The alternator was over charging sporadically.

 

[avalonandl]

These models have adaptive charging. That means at times it will charge more than others and it's not unusual to have the voltage range from 12-14+. My Denali often runs over 14.

That said Big mama is right to check cables etc....

OOPS- 2003 does not have adaptive charging.....

 

[SnowDrifter]

Put a multi meter on the battery and note voltage there

 

[Summajet]

I did not have time this week to check it over. Wife took it to local battery alternator repair shop. Technician said both battery terminals were loose. I will drive it and report back.

 

[OR VietVet]

Read thru this and check out those grounds: https://www.fixmyoldride.com/Chevro...e7e5cd24ed24635&at_ab=per-2&at_pos=3&at_tot=4

 

[2006Tahoe2WD]

PNW, Thanks very much for this link with info. on the regulated voltage control. This explains that the voltage moving doesn't necessarily indicate an alternator or battery issue.
In my case the voltage started reading higher than the usual 14.2 so I had the battery tested and then I got a new battery. The voltage was still high ~15 or maybe more so I suspected an alt. issue. I got the alt. rebuilt and the volts are about 14.9 and fairly steady. It could be my "new" battery is charging up and I will eventually see the volts come down after driving for awhile. Right now I'm just going to watch the voltage using my digital cigarette lighter plug in gauge. Thanks again.