Battery draining with key off

[KRN]

My 2008 Mazda 3i battery drains in 2 or 3 days with the key off sitting in the garage. The instrument panel light for "door open" stays on with the key off. The local Mazda dealer did some troubleshooting and tells me that I need to replace a 'junction box" under the passenger compartment right side fuse box. Cost $1,000 !!!. I think it has something to do with a stuck door open switch, but I can't find where the door open/closed switch is located on the door or frame. Pulling the left front under-hood 15 amp fuse #31 fixes the problem but disables the interior lights and electric door locks. This circuit draws about 1/2 amp with the key off (current measured with an accurate meter). Where do I find the door-open switches/sensors??
Thanks

 

[kms1990]

go to the dealer and have them pull the diagram of the door up. if that dealer wont do it have another do it. looking at my 08 3s hatchback the door open sensors/switches appear to be built into the latch somehow maybe behind the latch inside the door itself. i would definitely say having the dealer pulling up the diagram for the door would be the best and easiest way to get to the bottom of this issue you might try spraying the latches inside the door jams with wd40 or silicone spray (liquid wrench brand is great) and see if this helps as one maybe sticking. do all 4 doors and the trunk. the hood should not have any sensors. the haynes manual has nothing further than you have figured out. it just shows fuse 31 wires to the key switch and lights and thats all it says about fuse 31.

 

[concept]

Is the interior light staying on? I'm a bit puzzled as to how there could be a half amp current draw. If the door switch is not functioning properly, wouldn't just the interior light be on? If there is a short at the junction box, that should be something that can be fixed. I understand that the dealerships don't troubleshoot electronics at the component level, but if you can't fix the issue, yourself, you can always get a junction box at a junkyard if your gen car resides there.

 

[KRN]

Thanks very much for the response!

 

[KRN]

Oddly, the interior light does not stay on, just the dash red indicator showing door(s) open.

 

[kms1990]

Oddly, the interior light does not stay on, just the dash red indicator showing door(s) open.

try the wd40 in the door latches maybe one is slightly stuck and allowing the light on the dash to stay on but not interior lights.

 

[Keno1542]

you need to look at a wiring diagram to see what else is on that circuit. then test every item on the circuit until you find the item that is still drawing power with everything off and the doors closed. hope you are good with using a multimeter...

 

[concept]

Also, think about anything that was done to your car, just before this drain issue started happening. Was a stereo receiver, amp, or speakers installed?
Some Corvettes had weird issues like this because of pinched wires that passed through the driver's side door pass-through - a rubber accordion-looking thing that is visible when you open the door. a half amp drain is most likely a short (connection of power to chassis ground).
Many dealerships send vehicles to Auto-Electric shops. These shops troubleshoot and repair electrical issues, every day and are typically experts at what they do. You might also consider having one of them take a look.

 

[kms1990]

Also, think about anything that was done to your car, just before this drain issue started happening. Was a stereo receiver, amp, or speakers installed?
Some Corvettes had weird issues like this because of pinched wires that passed through the driver's side door pass-through - a rubber accordion-looking thing that is visible when you open the door. a half amp drain is most likely a short (connection of power to chassis ground).
Many dealerships send vehicles to Auto-Electric shops. These shops troubleshoot and repair electrical issues, every day and are typically experts at what they do. You might also consider having one of them take a look.

thats true as well we have a wire loom that runs through our door jams that has a wire harness in it and if you have done any after market modifications you have seen it and may have messed with it. i drilled a hole in the door and put a rubber grommet with a hole just big enough for the wire i was running around mine and wired my new speaker wires around the wire harness instead of in the rubber as i did not want to screw with any factory wiring as that can become a pain if anything gets messed up.