I have a 1999 ES300 with 88K miles. The battery has been going dead about every 3 months for 9 months now. I am wondering if the alternator has the voltage regulator built into it. Apparently the problem must be in the alternator or there is something draining the battery that is a slow drain and takes 3 months to flatten the battery. Jump the battery and it starts and charges and then starts just fine so the alternator must be putting out. I'm just looking for suggestions. I don't have any lights that are stuck on and I checked the trunk too. Any ideas?
Bugsy