Just bought an old fleet truck for my son to use as a beater with a heater. 2002 1500 two wheel drive with the 4.8 engine and automatic transmission. Back when these were new my construction company would have a half dozen of these rolling around and I was very impressed with how they held up. This unit appears to be in decent condition - but occasionally the "BATTERY" light pops on and the 4 gauges (gas, oil, volts ,temp) will start wavering back and fourth from max to min. After about 30 seconds or so the BATTERY light shuts off and everything returns to normal. Is this common? Do I have a ground or alternator issue? Gauge cluster issue?

 

It sounds like you have a ground issue.

I would go to https://lemon-manuals.la/ and look up the service manual for the truck and find the power and grounds location information and then dig in, undo the current grounds, clean and shine up the surfaces, and then refasten the grounds and hopefully, most of these electrical gremlins will disappear.

Good Luck!

 

Sounds like the ignition switch is going bad.

 

I have owned it a week or so now. It appears to have the fluttering gauges and warning lights during the first minute or so of startup. Once its run a couple minutes everything functions as it should. Is this one of the symptoms of a gauge cluster going bad?

 

Check the plug terminals first to see if they've spread apart and aren't grabbing the pins tight enough. I had bought one of these but never used it. The colors don't match but just make sure the wire connects to the corresponding wire in the harness. https://ebay.us/m/IID90z

I ended up getting the gauges s rebuilt here. The turn around was a week. That's shipping to and getting them back. https://ebay.us/m/TLh8GI

 

It could be one of a few issues. The first I would check is the ignition switch. If you wiggle the key with ignition ON, does it change the condition of the gauges. If condition changes by moving key in ignition, it could be the ignition switch. If the switch is okay, I would check the grounds next. If a northern states truck, corrosion attacks the grounds more, but normally just need cleaning and re-sealing/paint. The main one you want to check is the PCM and light harness ground on the frame, behind and left of the driver side parking light. You will see it through the bumper cut-out. Also, make sure you have the engine to firewall ground strap installed (commonly left off during engine repairs/swaps). It's one of the gray metal web straps connected to the back of the engine on the driver's side. I would also make sure the battery ground from the Red box to alternator end connectors are in good condition. That wire is undersized. I replaced mine with a 4.0 ga. The fourth and last I can think of is the alternator voltage regulator. It may be telling you to open the alternator for repair. I hope one of these helps.