My voltmeter shuts on and off about every 30 seconds and the lights dim during the needle sweep. No other issues happen during the sweep, truck runs fine and the radio keeps playing. No hiccups other than gauge and lights. Any suggestions?

 

get your alternator tested. i know theres another thread about a similar issue but i dont really recall what the solution was. i'd start with testing the charging system though

 

Check the alternator plugs too. Mine has melted several times.

 

The ground above the battery was loose, didn't fix the problem. The alternator plugs seem to be good. The fade/glitch/short is on a cycle, I tried to count evenly and every 24 counts the lights would fade. So what would cycle like this? Any ideas?

 

Is the A/C compressor kicking on every 24 seconds?

 

Sounds like your voltage regulator is acting up. Depending on what year you have some are external and some are built into the alternator. Take it to autozone and have the charging system checked out. Or you can do a voltage check at the field terminal on the alternator or regulator with a voltmeter.

 

Autozone checked the charging system and no problem. At idle, during the draw the idle does drop. I will try the AC tomorrow and a voltage check on the alt/reg this weekend. Could a fuel pump cause an issue like this?

 

BINGO, we have a winner. Aliens8myCow wins the grand prize. Unplugged the AC and the cycle has stopped. It looks like it's time for a new thread.

 

Yay!!!

Wanna know how I knew that? Mine does the same damned thing...

Wanna know how to fix it? So do I!