Mystery battery drain in 2012 Tundra

I have a 2012 Tundra with low mileage, and a 3 month old battery. When I shut it off & remove the key, the digital dashboard clock stays on, as well as the radio & shift display light (P for Park). When I charge it with a 12 volt charger for 6 hours, it is fine, unless I do not drive it for 24 hours. Then, it's dead, no clicking, nothing. I had the dealer remove an aftermarket remote starter, and I had an Autobody shop replace a rear passenger side door, which I'd badly damaged. They checked its door switch & it was fine. Anyone have any suggestions? I'd sure appreciate any. In the 2&1/2 months with the new battery, it's died 5 times!

 

I hope someone can help with your issue.

 

Did the issue start after the remote starter was removed?

 

You don't have a Bluetooth adaptor plugged into the OBD port or something like that do ya? Those are good for a slow drain.

 

Obviously, those lights for the clock & the shift display light are draining my battery, but why are they not shutting off when I remove the key? The radio I shut off manually, but I can't do anything about those lights, short of pulling the fuse. I should say, the main dashboard lites do NOT stay on when I pull the key.

 

The problem started before I had the remote starter pulled. Indeed, that was the reason I had it removed, thinking it was contributing to the drain. I do keep a cell phone charger plug in the lighter socket, tho I removed that when I had the door replaced, & it is still dying on me.

 

I DO appreciate ur helping me puzzle this out.

 

If you have nothing on the OBD port keeping it awake, then my next guess is something wrong or not undone from the remote start removal. If you know the mfgr/brand, I would comb the install instructions and work backwards to verify any wiring mods. Have you tried testing the ignition switch?

 

If the truck is new to you, I would look hard for any wiring mods. If this is all the sudden, I would suspect some type of component failure. Electronic gremlins are the worst...good luck.

 

Parasitic battery draw is the worst... been there done that and it sucks... what you first might want to do is when you turn off the truck make sure you turn the key all the way down as to ensure it's closing out the hot circuit. If that doesn't work, then grab your multimeter and start looking for the fuse before chasing wires. Odds are you will find the draw this way and solve your issue.

It sounds like truck thinks they key is still in the ignition leaving some accessories on which will drain your battery.. easiest way to test this method is sit in your truck with door closed and turn the key to accessory have all your dash turn the key all the way off, pull the key and open the door if stuff doesn't turn off then there is an issue beyond that point and start the fuse check. I would start with the inside fuses.

 

If you don’t have a multimeter you can also use a tool like this

 

If it started before the remote start was removed I would venture my guess that one of your relays that controls accessory power has gone bad and doesn't turn off when you remove your key. I would lean towards that rather than fuse failure since normally when a fuse fails things tend to not turn on, not the other way around. To properly fix your problem is going to be a challenge since you will have to find where the problem originates in the wiring, or if you just want the problem to go away you can fix it the wrong way and install a truck kill switch. @Mountun Goat just did this to his truck to solve a different issue he was experiencing, but, it would make your problem go away all the same. Here's a link to his mod https://www.tundras.com/threads/mountun-goat’s-anatomy-thread.25483/page-15#post-1992467 I'm sure he would help you out if this is the route you decide you want to go.

 

Thank u, Palm Tree. Ur diagnosis makes sense, particularly the point about when fuses fail.

 

I did a little bit of digging because I was bored. I found this site that laid out the fuse/relay box under the hood. I have no idea if it is a direct match for your truck but you could confirm that by looking at the diagram on the inside of the lid of your fuse box in the truck.




#42 seems to be the relay that I would start your troubleshooting at. It controls just about every function inside of the cab. I don't know the exact steps to take to figure out whether or not the relay is bad but maybe someone else can jump in here or maybe you know someone.

Edit: Here is the site as well if your interested https://imgvehicle.com/toyota/tundra-ii/fuse-box#post286