My son has a 2006 Silverado with only 46000 miles that keeps killing batteries. A new battery will only last a few months before it quits holding a charge. Charging system checks out ok charging at 14.2 volts. I have also noticed the dash lights flicker when driving at night. Any ideas? Thanks.
With a new battery and a charging system charging at 14.2 this would be considered normal then you would then need to check for a parasitic draw on the battery and make sure all body and engine grounds are free of corrosion. If corrosion is seen remove ground cable or wire and clean surface and reconnect wire and make sure connection is tight.
The best way to do this is to let the truck sit for about six hours to make sure all modules in the truck are in sleep mode. Then check for a draw on the battery that is no more than .02 amps.
When diagnosing battery draws on trucks equipped with the automatic dual zone HVAC controls (RPO CJ2), technicians should keep in mind that the control head does not completely "go to sleep" until after 150-250 minutes, or up to 4-1/4 hours, from when the ignition key is turned OFF. This is a normal condition. In these cases, DO NOT replace the control head. This is why you need to wait for at least 6 hours before you start to check for a draw on the battery.
Driving habits can also cause a dead battery. If the truck is driven only once or twice a week or just going for short drives; this is not enough to recharge the battery and can cause unnecessary diagnostic procedures.
If there is no parasitic draw and the charging is in normal range then these are consider normal operating conditions.
Get back to me with more information on your sons driving habits and if there are any ground issues on the truck. We can continue to diagnosis the problem from there.