HyundaiKitCoupe

I'm having a weird problem. My car battery discharges overnight and it needs a jump the next day. All the doors are locked, lights off...etc. Everything is off. The only problem is the door button (the one that activates the interior lights and jingle) sometimes does not come on, but otherwise it's shut and I don't know what would be draining my battery? Could it be the faulty door button?

DTN

This can be a tricky problem. First things first, make sure to disconnect any audio equipment which you have added and then have your alternator and battery tested at Autozone or Advanced.



After that, troubleshooting can be a long process. Disconnect fuses one at a time, turn off the car and hook up a very small 12v bulb to each fuse to see which one is drawing power. If you don't see anything, try using an LED. If the LED blows up in your hand, then you found an active current source. Do this to every fuse in the engine bay and every fuse in the passenger compartment. The purpose of the LED is that it will emit light and activate at a lower level then the 12V bulb.

daytonmvp23

^agree with this or if you are planning to do a lot of work on the car go to Harbor Freight or sears etc and pick up a multimeter and set it to DC Voltage for the same test. Also check at the alternator and starter they are linked directly to the battery so if the regulator or solenoid are faulty sometimes they can be the source. But yes if you have a custom system or alarm system these are usually at fault. Then it is off to the fuses fun times

HyundaiKitCoupe

So far I have checked all of the fuses and all are okay.



I will test out the connections in the morning. Thank you both.

DTN

You can't check leakage with a multimeter. Plenty of fuses will have 12v potential. They should not be able to light a light bulb though. That's checking amperage. If you set your multimeter to amperage you will likely burn wires or blow the multimeter fuse. A bulb is regulated internally with its resistance so it can only add resistance and act as ab indicator of power flow.

SR Tech

Your battery finally kicked the bucket, get a new one.



You guys are making this more difficult than it should be.

Turboron_99

You can do a check with a multimeter for current draw..



This is easiest with two people!!!



Turn everything off like you normaly would leave the car for the night!



Pop the hood



Disconnect the NEGATIVE cable from the Negative termainal on the battery (dont let it touch anyting, it will spark!)



Now set you multimeter to read in Amps



Put the positive lead form the multimeter, on to the negative post on the battery!



Now take the negative lead from the multimeter and connect it to the ground wire that you just took off of the negative post...



If you see anything higher than .05 You have something draing, if not, then take the battery in to get checked out, more than likely you have a few dead cells and the battery wont hold a charge!!!



Hope this helps!

tibbytib

^^Agreed, you definitely CAN find a current draw using a multimeter. I did. Not sure if exactly how I did it, but, Turboron_99 is correct I think is his explanation. I found a current draw coming form a boost gauge by all things!!! Its an easy check. THen you can either take your battery in or start searching for the current leak.

DTN

Except you are measuring a short and it will likely pop your multimeter. Just sayin. People try to measure amps but end up with a bad multimeter and read 0a across each fuse. It's best to take an indirect measurement like using the smallest 12v light you can find.

Turboron_99

DTN. here are the simple characteristics of a "short", when resistance is 0, in a short you cant measure voltage because you cant have voltage with no resistance!, voltage across a short would be 0, the only thing you can measure to find a short is Amps, now i do understand what you are saying, but if you have a multimeter, then you should be able use it. Just doing a current draw check will save you time.



A short will not "POP" a multimeter, a short will melt your amp fuse in the multimeter if you forget or simply dont know how to set your multimeter to read in Amperage.



I highly suggest to do a current draw if you ever have any battery issues, very simple way to tell if it is indeed related to a short in the car, or a bad battery.



Also if it was a "short" the complaintant should have noticed lights went our, or a gauge stoped working, as if it was shorted, the voltage would take the path of least resistance, and the short would be where the voltage would go.



So another question, are all your lights working, turn signals, brights, headlights, interior lights, stereo, lock.. etc.....???