Current draw killing battery(s)

[Keith Seymore]

Howdy everybody.

Vehicle is a 2004 2500HD Duramax.

I have a slow draw which can kill my batteries overnight.

I unhooked the power and jumped one battery with a test light (ie, from battery positive post to test light, then test light to positive cable. One battery only; other battery positive cable disconnected).

I pulled every fuse and relay one at a time in the underhood BEC, the LH end of the instrument panel and inside down by the driver's left foot (boy - are there a lot of them).

None of them killed the draw.

Is there another fuse block I'm not thinking of? Is there something drawing power that is not fused?

It has an aftermarket remote start that I do not use; I have an aftermarket electric fuel pump, which is one of the fused connections that I pulled. Also aftermarket trailer brake controller. Everything else is OE.

Thanks in advance -

K

[Keith Seymore]

Update: unhooked the remote start, unhooked the fuel pump and unhooked the trailer brake controller. Physically removed the radio and HVAC control.

No change.

K

Linking this thread for reference: https://67-72chevytrucks.com/vboard/...d.php?t=842257

['68OrangeSunshine]

Hi Keith,
I just got an '03 Tahoe C/1500. Batt was an EverStart with a 2/24 sticker. [but no warranty paperwork from the PO]. Truck had connection issues in the rain. POS terminal bolt has plier chew marks. Week before last it started OK with a turn tightening the terminal. Volts were 12.7. Monday tried to take it to work -- no start. Grabbed '71 Jimmy and got to work Monday and Tuesday. Weds, I checked the batt, 6.3 volts. W/O paperwork I didn't go to Walmart, I was going to use it as a core on a new batt from Interstate. The guy there said, 'let's see if it will take a charge,' so they have it overnight.
But a drop of six volts on an unused truck seems extreme. Not used to these ''New'' trucks. ALL the door locks open when I go into PARK. Window up/down switches have been playing tricks, and the DS RVM will go screwey when the rocker switch goes over to adjust the PS RVM. Pass Side mirror is stuck at curb view.
[I had it adjusted fine until I showed off my ''new truck'' to my next-door-neighbor, and he said ''what's this do?'' and poked his finger on the mirrors switch and both mirrors went nuts.]
I pulled the 15@ fuse for the RVM but that also killed the window up/down circuits, so I put it back.

[hatzie]

The middle bussed electrical center is next to the parking brake pedal and there's one on each end of the dash.

The trailer brake controller should plug into the mid BEC and there are two trailer connections in the fuse relay block behind the LH battery.

I would check the trailer plug. I've had winter calcium slop make enough of an electrically conductive crud slurry in the trailer plug to drain the battery. I blasted it out with brakeclean and a nylon brush then hit it with battery protectant.

[Randy S]

Disconnect the alternator, including the R1/R2 plug.

[68Gold/white]

Originally Posted by Randy S

Disconnect the alternator, including the R1/R2 plug.

Diode sticks closed, one of most common drain problems.....

[Keith Seymore]

Thanks for reminding me -

It ended up being flat batteries.

I replaced the batteries and all my problems went away. It wants to fly now.

Amazing what you can get used to and begin to think of as "normal".

K

['68OrangeSunshine]

The battery on my '03 Tahoe came back up after a long charge. It seems to be charging and operating normally after 6 weeks.