What is causing battery drain?

[bbdmcm]

94 Full-size blazer sport, have been through 4 batteries in last 6 months.
The 1st 3 batteries lasted about a month, realized a light switch was left on..turned it off, the last battery lasted 3 months..now blazer wont start..but interior lights come on..pleae help

[Rick Norwood]

Originally Posted by bbdmcm

94 Full-size blazer sport, have been through 4 batteries in last 6 months.
The 1st 3 batteries lasted about a month, realized a light switch was left on..turned it off, the last battery lasted 3 months..now blazer wont start..but interior lights come on..pleae help

It sounds like your Alternator is not charging your battery. You should be able to drive into your local Autozone or Checkers and get them to do a free charging system check. It is a good place to start.