Mystery battery drain
 

Ok, I've got a mystery that perhaps someone on the forum can help me solve. My grandmother has a 2007 Camry LE and the battery just keeps draining. Sounds like a simple problem but apparently not. We took it into a very reputable repair shop and they did a thorough inspection and ruled out all possibilities other than it just being a bad battery (even though we had just replaced it a week prior due to the same issue). They said its def not the alternator or a charging problem or an electric drain. We were skeptical that it was the battery since it had just been replaced but we went ahead and replaced it again and the exact same issue came up again. If its driven daily its fine but if its driven less than twice a week it drains within 2 weeks. Ive taken my vehicles to this repair shop for years and they are very highly rated. I have a hard time believing that they could overlook anything that would be considered a common issue. Anyone else experience this issue? Any thoughts?

Does the car have an aftermarket installed remote, alarm, stereo, stereo amp, etc or auto off lights?

Is the driver leaving anything like an iPod plugged into the cars stereo?

Is the cars climate control manual or auto?

Is the shop replacing the batteries for free?

Is it possible for to leave the battery disconnected until the next 2 week drive? Or when visiting the owner, to check the battery voltage with a voltmeter.

One Camry owner found their cars heater/AC fan was turning on as the car sat while they were out of town.

No aftermarket remote, alarm stereo etc.
Nothing plugged into the car stereo
I believe that the climate control is all manual but the user manual doesn't make clear whether this model has auto option. it doesn't appear that it does based on the dash controls. What does it look like to you?

https://cimg8.ibsrv.net/gimg/www.cam...4a366405f3.jpg

The shop wasn't replacing the batteries for free. We did that ourselves.

I just charged the battery fully last night. I checked it with a voltmeter a couple hours after charging and Its reading just over 13 right now but that may be due to a surface charge. Ill check it again in a few hours.

"One Camry owner found their cars heater/AC fan was turning on as the car sat while they were out of town." hmmm..I wonder how I would check to see if this is a possibility. Any ideas?

It's a manual climate control system.

If the issue is uncommanded loads and NOT a bad alternator, battery, parasite drain finding the problem may be challenging. Suggest to reconfirm what the shop stated.

With engine running at approx 2000 RPM, battery voltage should be 13.8v -14.7v due to the alt output.

Approx 20 minutes is the rest time between last engine on and checking battery voltage. If needing to check sooner. Remove surface charge by turning ign ON plus electrical items such as headlight, blower motor, rear defogger etc.) for 60s. Turn all off then check battery voltage. Should be 12.5-12.9v.

To check for parasitic drain, use a milliamp meter installed between one of the battery terminals and its cable.

Read the posts at the link below referencing the climate fan AND auto on/off headlight issues that might lead to a dead battery.

https://www.camryforums.com/forum/ec...y-again-38140/

Door lock computer failure can also cause problems.

Could install a voltage data logger such as below. Then check voltage vrs time. If something does turn on by itself, the voltage should drop..

http://www.testequipmentdepot.com/la...iAAEgKqefD_BwE

Thank you for the link to the other forum topic. Sounds like I'm not the only one who has had this problem with these vehicles.

I checked the battery with a voltmeter at 2000 rpm and it read 14.2v so all good there. Before I started it up, it read 12.9v so its not draining super fast (that was after about 6 hrs from fully charged)

The headlights have been off (not on auto) so I don't think that is the problem. I'll need to check the climate fan as well. How would you recommend doing this? Putting a tissue over the vent and seeing if it moves? Can I put it over the defrost vent near the windshield? Wasn't sure if it automatically blows air from that spot when the AC/heat is on.

I don't have a mA meter or a voltage data logger so i can't do those tests at this time.

Seems like Id have to take it to a Toyota dealership and hope that they have seen the issue before.

The fan motor RPM is controlled by a computer. If you thought the issue was the fan, could unplug the wiring harness connector at the fan motor.

Toyota did have the climate vents reverting to say recirculation under certain circumstances. Suggest reading the owners manual in regards to any default climate mode settings.

When putting down a tissue, make sure the proper climate control vent is selected for the vent having the tissue over it.

Does your voltmeter have a milliamp setting?

Problem solved
 

I ended up taking it to the local Toyota dealership. They quickly determined that there was an aftermarket security system that had been placed before the vehicle was purchased. We had no idea that it was even on there. Apparently the security system had a short which was the cause of the parasitic drain. Problem solved!

Great job!

Thanks for posting back with the find.

My issues
 

Had rad replaced on 2010 Camry 2.5l Se., manual heat / air system but car has aftermarket car starter .15 minutes after driving off lot car shuts down. What should I do?Thanks

My issues
 

Had rad replaced on 2010 Camry 2.5l Se., manual heat / air system but car has aftermarket car starter .15 minutes after driving off lot car shuts down. What should I do?Thanks