I hope you guys can help ive been having electrical gremlins since january. I Replaced the battery in my 1999 silvy (4.8) back in july of 05 the stock battery finally gave up the ghost the negative side terminal fell out of the battery. So i replaced the battery truck drove fine no problems drove it everyday. Dec i leased a new sierra so the silvy sat for like a week and the battery died, jumped it ran fine then within a few days it died again same scenario it died within a few hours. I replace the battery with another new battery, july or there abouts same problem talked to a couple of people said to check the alternator i tested the alternator on an osciliscope and it appeared one of the diodes was going bad so i was told that possibly after the diode gets hot when it cools down it would draw juice back in so i replace the alternator (had 98,000 miles at the time) well it was good while i drove the truck everyday but i let the truck sit and it did the same thing so i took out the battery which was dead as a door nail and put it on a charger gave it a full charge and within a day after letting the battery sit i checked the voltage and it dropped two volts on its own within a day, so i replace it under warranty. since june i have replaced the alternator belt, alternator and battery, yesterday while driving from hamburg pa back home the battery light came on 5 times for verying amounts of time usually a few seconds during this time i didnt see a voltage drop on my dash panel gauge it still showed slightly over 14 volts. So what to do next i am going to go back and unplug the alarm then the lights i added (mostly leds) and just try one thing at a time but anyone have any idea what else to look at is the pcm going to squat. sorry for the long post if someone can help i would appreciate it. dan

 

no one has any thoughts or ideas?

 

What brand of alternator did you replace it with? I have had a couple friend have the same problem. They got napa replacement. Tried three of them they each only lasted a couple of weeks. Most of the one you get a an auto part store are going to be cheep rebuilds. Don't wast your money. Take your OEM Delphi to a alternator shop and have them test it or rebuild it. Could be a bad ground wire. Replace the battery ground wire Make sure every thing is very very clean. You should also do a test like this,http://flashoffroad.com/electrical/C...rrentdrain.pdf

Hope this gives you some options. Let us know what you find out.
Good luck these things can be a big pain in the ***.

 

does your truck have alot of aftermarket sterio equipment/screens/electric starters or any other crap in it?

go to an o-reily and have them hook up to your battery with their machine. they can check the battery and the alternator output at the same time. if the post fell off the battery i assume your wires look nasty. what most people dont understand is that that cable looks like that under the insulation too if its a sevier case like yours sounds like.