Hunting a battery drain on Fuse #11

[Donald Milton]

My alternator went out, replaced it, drove about 35 miles home, got out and next morning battery was dead. It was about 2 years old, so as a precaution, replaced it. Was OK for a day, talked about potential of bad alternator so got a second replacement for it. Now I am on my second replacement alternator and first replacement battery. Truck sits for a day and night and its a dead battery again.

This time we isolate #11 fuse as having a high battery drain, pull it out and truck cranks up and maintains a battery charge for last four days. I know this circuit, #11, controls the radio. Does anyone else have a list of other applications on #11 fuse and how to isolate them?

 

[DG1959]

2002 - 2009 Ram 1500 & 2500

Fuse 11 handles -

Radio, Media System (Monitor/DVD), Data Link Connector, Hands-Free Module, Satellite Receiver, Cluster, Sentry Key Remote Entry Module, Underhood Lamp, Wireless Control Module, Electronic Overhead Module

found it here:

Fuse Box Diagram Dodge Ram 1500/2500 (2002-2009)

Fuse box diagram (location and assignment of electrical fuses) for Dodge Ram / Ram Pickup 1500/2500 (2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009).

fuse-box.info

 

[Donald Milton]

My bad, 2007 Ram 3500 5.7L gasoline.

 

[DG1959]

2007 Ram 3500 5.7

11Fuse MINI20A

Ignition Off Draw. (IOD)-Cabin Compartment Node (CCN) / Radio / Under Hood Lamp / Wireless Control Module (WCM) / Satellite Digital Audio Receiver (SDARS) / Hands Free Module (HFM)

 

[DRAXSON]

Hey there Donald, did you ever get this figured out? The circuit related to this fuse is pulling a little over 3 amps in my rig. Drained a new battery in days. Trying to figure out which component is the culprit

 

[Slinge]

I would look at under hood light 1st

 

[Grams]

Underhood light doesn’t pull 3 amps. That’s about ten-times it’s draw.

 

[Slinge]

Easy to check for sure !

 

[DRAXSON]

Thanks Slinge. The light itself is out, I'm assuming it's just burnt out but I followed the wiring into the main part of the harness it comes from, nothing looks messed up

 

[Oliver Closehauf]

This happened to me. It was the stock power amp for the radio staying on. Some times pulling the fuse would disconnect the amp, some times you could play with turning the radio on and off, but in the end I just replaced all of it with new aftermarket Infinity amps and speakers and an Alpine head unit.

 

[DRAXSON]

Oliver thanks for the info, I noticed the amp has a separate fuse in mine, number 36. Did yours have the same set up as well?

 

[EricKBattleGround]

Sorry for a long post - this might help you understand the gremlin that you are chasing. Or not.

The IOD fuse is not providing primary power to any of the electronic systems that are connected to it. The under-hood lamp isn't an electronic system, so that is a bit of an exception. Any controller connected to the IOD fuse will have a separate primary power feed, with a separate fuse. I only did a quick glance at the '06 Ram workshop manual's wiring diagram section; F11 "fans out" via wiring harness splices to different systems including (but not limited to) the instrument cluster, hands-free system, and radio.

The IOD fuse keeps the various electronic modules in an "ultra-low-power" state - if not in this state, there can be...interesting...issues as the various electronic systems come alive. Nobody likes to troubleshoot a list of 15 different fault codes that basically boil down to "I didn't get the message I expected when I started".

IIRC, the Owner's Manual recommends removing the IOD fuse if a vehicle won't be driven for about 3 weeks - which suggests the normal IOD fuse draw for all devices that are connected to it should be significantly below 0.5 amp - and possibly well below 0.1 amp (100 milliamps). For what it's worth - the underhood lamp, if stuck on, would likely drain a single battery over a weekend, and a dual-battery truck like mine in a week. My guess is that the current draw of the bulb is around 0.2 amp - about the same as a courtesy (dome) lamp inside the cab.

This could be a tough nut to crack, considering how the IOD fuse is "fanned out". To me, it seems like the troubleshooting would involve disconnecting everything attached to IOD power, checking the current draw, and then reconnecting devices one-by-one - or some variation thereof. Another poster indicated that audio systems might be the culprit, and maybe disconnecting audio systems first - checking IOD current draw before and after - would be a place to start.