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Discussion Starter · #1 ·
Over the past several months, my battery has twice been completely drained on my 2004 Sonata. The drain has been so bad that I had to take the battery to an auto parts store to get it charged. In order to find the problem I began looking for how much power the car was drawing when everything is off. It ended up drawing 4-4.5 amps. That would drain my battery in less then 2 weeks.

I started pulling fusing to see what circuit had the vampire. When I pulled fuse #24 (pwr fuse 2), the number of amps drawn fell to something like .04 amps. My issue now is I don't what system is beyond that fuse. I bought a Chilton Repair manual to help, but that fuse does not appear to be listed in their wiring diagrams. Someone suggested to try disconnecting my clock and radio, but that had no effect.

Any idea what system(s) I need to be looking at so my battery isn't being drained?
 

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Well, 4A will drain a 68Ah battery in less than a day.

According to my Kia optima wiring diagram, 30A pwr-fuse2 (inconsistently also called I/P B2 in other spots of the document) of the engine bay fuse box feeds via the interior fuse box into:
a) the 10A D/Clock fuse and from there goes to the instrument cluster (positive supply for all kind of ground activated lamps such as 'door open'), clock and radio memory supply, climate control (memory retention again) and ETACS unit .
b) the 10A Room fuse supplying power to interior lamps, trunk lamp, electrical antenna
c) the 15A D/Lock fuse for the central locking.

EF/B Sonata expected to be the same since it's basically the same vehicle.
So I'd suggest to drill deeper by pulling the candidates b and c (you already tried a without effect). My bet is 'b'.
 

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Isn't the fuse block labeled at to what that fuse powers?
 

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Nope. That would be too simple ...
The engine bay fuse box says pwr-fuse2 (also in the UM), The interior fusebox says clock, room and lock but nowhere it says that pwr-fuse2 feeds these 3. That is only to be found in the detailed wiring diagrams.
 

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Discussion Starter · #5 ·
The fuse box is marked pwr fuse 2.

I pulled fuses from the interior box for the lamp and locks, no change to amps being used.
 

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If you pull all 3 and still have 4-5 go over the 30A fuse I would suspect that there is a wiring problem between engine bay and interior fusebox. Are there any 3rd party (previous owner ...) installations present ?
 

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Here are the three fuses that are supplied with power from pwr fuse 2...
451108


If I helped you fix it, why not...

Your support is greatly appreciated
 

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Discussion Starter · #8 ·
I just went back and pulled the clock fuse, rather the disconnecting the clock and radio as I did before. That dropped amps. So the issue appears to be after the clock fuse.

Anything other then the radio and clock on that fuse?

A third party radio was installed, but I've owned the car for 9 years and this is the issue I've had, although it was my daily driver so it might have charged enough to keep going. Stay at home orders cut my driving so that might be why it is manifesting now.
 

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Discussion Starter · #10 ·
Where is the keyless entry Module? My kids were playing with my keyless entry before the issue started.
 

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Just a thought at night with your trunk closed but you inside the car flip down the back seats and see if the trunk light is staying on.
 

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Where is the keyless entry Module?
Looks like it's behind the heater control panel...
451134

Just a thought at night with your trunk closed but you inside the car flip down the back seats and see if the trunk light is staying on.
Worth a look I suppose, but he'd need to have a headlamp bulb in the trunk light for it to be drawing 4~5Amps.

If I helped you fix it, why not...

Your support is greatly appreciated
 

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headlamp bulb in the trunk light
Who knows ? wouldn't be the first time that important additional information comes from OP after several iterations of numerous people shooting in the dark.

I did not get the message right that the clock and radio were disconnected as individual devices since I'd start with the d/clock fuse in such case and drill down to device level only after that ...
 

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Discussion Starter · #14 ·
Solved. I had a Bluetooth obdii scanner plugged in before the lock down started that I forgot about. Looking at night for the trunk light I saw the glow of the scanner and remembered it.
 

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Glad to hear that.
I suspect there is something seriously wrong with your bluetooth VCI or your ammeter though. There is no way an OBD scan tool should be drawing 4~5A of current.

If I helped you fix it, why not...

Your support is greatly appreciated
 

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Guess the meter is toast or wasn't used properly.
As calculated before, 4-5A practically drain the battery in a night. If the OBD thingy pulled that much it'd glow itself, not just the leds on it. More likely it pulls 100-400mA.
 
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