What could be wrong if I have went through 1 battery per 1.5 yrs in my 2003 Denali and diagnostics say that my alternator is fine?
Depends, u may do a lot of short runs which dont charge the battery up, u may live in a cold area which hurts the cells or you may be putting the wrong battery or a low quality battery in, some cheaper batteries only last around 2 years. Alarms can cause problems for sure if its not a factory fitted one and drain the battery or something is wired wrong or shorting taking charge from it when the car is off.
Search GMC Yukon Questions
GMC Yukon Experts
Related Models For Sale
Used Cars For Sale