2002 Silverado Battery light and low voltage on gauge

DebH_MS · March 19, 2013

So I have a 2002 Chevy Silverado LT Stepside with 4.3 V8 vortec engine. Just replaced the battery within the past 4 or 5 months. Start it up and battery light comes on with low voltage reading in the dash gauge (12v or so). When I can get to open road I floor it and the voltage goes back up to just over 14v and the light goes out. Any ideas??

Here are all the factors of the equation: neighborhood roads ripped up and very bumpy - possibly loosening the connections and/or getting all kinds of dirt. Feel like I'm off roading in my own neighborhood. Truck bought used 5 years ago with 72k miles on it. It has a power converter with a 220 outlet in the bed. The interior has been replaced thanks to whoever set it on fire. It has also been in a flood that got into the cab (carpet only). It has run fine until recently. Oil changes have been routine and use full synthetic. Tranny needs flushed, but since it has neved been done and just hit 130k miles and afraid to commit to it due to the fact that it has a hard shift every now and then. Also has the low coolant light come on, but have had that problem for nearly 3 years and just add coolant. I am thinking the coolant level drops to a possible leak in the line somewhere.

Help a girl with a truck??

Chris · March 19, 2013

Have the battery and alternator tested. Then go from there. Post results if possible

Also the 4.3 is a V6. So is it a 4.8 or 5.3?

DebH_MS · March 20, 2013

Sorry, 4.8L. I always get confused on that part. I know for sure it is a V8. =)

Chris · March 20, 2013

But go to Auto Zone or any other parts house and they will test the system for free

DebH_MS · March 23, 2013

So Auto Zone was a complete waste of time, the one here has nothing but LAZY, go for nothing personnel. The guy tried to tell me that he can't test the alternator unless that battery is fully charged. So, took it down to Advanced Auto parts - great service there!! The guy came out to the truck and tested the battery and alternator. Then took off the postive battery cable and the truck stalled. So, it is a bad alternator.

So, all you guys out there tell your wife, daughter, mother, girlfriend, neice or whoever, that it pays to pay attention to the dash guages and lights ALL THE TIME!! At least I knew there was something going wrong. And apparently that is how you will know that your alternator is going out on a Silverado. =)

Chris · March 23, 2013

Good. It's always a good idea to have that stuff tested first.

68haywagon · March 23, 2013

The guy came out to the truck and tested the battery and alternator. Then took off the postive battery cable and the truck stalled. So, it is a bad alternator.

I cringe whenever I hear about or see someone doing that. Never pull a battery cable on a modern computer controlled vehicle to test an alternator! I'll give you the number to someone who did that in my parking lot after the test we did for him. His alternator passed the test and he didn't believe me. He disconnected the cable to the battery and the truck revved up and shut off. He goes see it's the alternator! When he hooked the battery back up...crank no start and radio and power windows inop. He fried his PCM and BCM because of a voltage spike from the alternator when he disconnected the battery. Cost him more then an alternator thats for sure.