Battery being drained

Diagnosing A Car Battery That Runs Down: http://www.aa1car.com/library/battery_runs_down.htm - How to Find a Parasitic Battery Drain: http://www.wikihow.com/Find-a-Parasitic-Battery-Drain - you should also get the charging system (battery, alternator) tested, you can get that done for free at any of the major auto parts stores.

charge it up, disconnect the ground and let it sit, if it starts a few days later you are correct somethings pulling it down while connected and not the battery plates shorted and internally draining it., darn near half of condemned batteries traded in are still good, like pcm,s used to be,

I've done that and have replaced it with a new battery and still the same issue. Tried every relay and fuse as well. Been trying it all.

turns out it was the celenoid for the starter.

I wondered about that. My 2005 Highlander dies after several days in the garage, but only in Winter. The dealership says I just don't drive enough, and says the solenoid is unlikely to be the problem (but they will happily charge me $450 to replace them). I've had previous cars that could sit outside for weeks and start right up, so I never trusted the "not driving enough" claim. And I'm going to try that "disconnecting the battery ground" test. Together, we may pin down the Toyota battery problem...

Good luck. It was a long process to figure that out.

My sister has a 2017 Highlander XLE. Same problem. Same time frame (two or three days idle). They have put 3 new batteries in the vehicle. They want her to run a trickle charger. What a bunch of bull. The last "expert" wondered if her home wifi connection was too close to the garage. WTF! They say the solenoid isn't the problem.

Same problem on 2006 Highlander. Battery dead after a couple of days.

2013 highlander. Battery would go dead if not driven daily. Through trial and error, discovered that when the automatic lights function on light stalk was left on “automatic” when not driving it a lot, the battery would go dead. I now always turn lights on and off the old-fashioned way.

2008 highlander I replace the battery every year almost to the month I f I stop at a rest stop and use the radio while napping the battery has died. Had it checked yesterday. Alternator charging at correct voltage. So it’s a possibility of the starter solenoid or auto lights.

I have a 2012 highlander and last year, I changed alternator, starter, Fuse and battery. This winter, the battery is dying if not driven daily. Car stays in Garage. Not sure, what to do?

I have a 2007 highlander hybrid and every 2 years, almost exactly in October, the battery dies. I take it to the toyoto dealer and they cannot find anything wrong. So a new battery comes in again this year 2021. This will be about the 4th battery, I've owned the car for 8 years. What the heck is up with this toyota car battery?

Our 2012 highlander kept draining batteries ( three in a year. ) Happened again so at the dealer, they believe it is a bad positive battery CABLE. With the old cable, alternator would not deliver enough voltage to keep the battery charged. They replaced the whole cable and now 14 volts reaches the battery. They are also doing a parasitic drain test on all fuse runs. They are pretty sure it was the cable.