Battery Run Down Protection

[20Silverado11]

In examining my window sticker, I've got a standard feature on my 2011 Silverado LT called "Battery Run Down Protection". My owner's manual does not make any mention of this, so I don't know how it works. The search feature of this web site yielded 0 results, so I tried Google. What I found was an article (http://news.pickuptrucks.com/2009/11/gms-new-battery-saver-feature-can-save-tailgaters.html) saying that you could use all your 12 volt accessories (in our case, the attached interior lights in our horse trailer) - all the while, the Battery Run Down Protector system would monitor battery voltage. Once voltage drops to a pre-determined minimum amount needed to start the truck, it shuts things off until you restart the truck and recharge the battery. So - have you tried it and is this how it works? I don't want to be out somewhere thinking that I know how it works, only to have a dead truck that won't start. Well, I guess we could just ride the horses to wherever we're going, but that still leaves us with a dead truck...

 

Marc

[MS3DALE]

I'm not as familiar with it as I should be,but I don't think it will protect the power supply to the trailer from draining the battery,I think it just covers the lights on the truck itself.

I think if you leave the lights on on your horse trailer it will drain the battery,someone else on here I'm sure is more familiar with this than I am.

 

Heres what is says in the service manual...

 

Battery Rundown Protection/Inadvertent Power

The body control module (BCM) inadvertent power supply voltage circuit provides battery positive voltage to all of the interior reading lamps, visor vanity mirror lamps, and cargo lamps if equipped. In the event that any of these lamps were to remain illuminated for a period of more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total battery discharge condition.

[mfennema]

I know that in my 07 if you leave any of the lights on they will automatically shut off after 10 minutes. Same as if you leave a door open, the light will go off eventually with the door still open. Maybe this is the same thing??

 

I have my underrail bed lights connected to the continuous power that I have hooked up to my hitch connector and they will stay on all night if you don't turn them off.....believe me, I know. So I agree with Rich, you can run your power down through the hitch connector if you leave something turned on thats connected to it.

[20Silverado11]

Thanks for the replies guys. It's a good thing I asked before I just went out, assuming I knew how this thing works, and wound up at some remote trailhead, at night, with a dead truck.

[SparkySparks]

My understanding is its only lights and internal power points that are "protected". The power at the 7-pin is more or less the same as having it hooked straight to the battery.

[MaverickZ71]

Here's what the General says in my 09 Silverado's owners manual:

 

Battery Run-Down Protection

This feature shuts off the dome and reading lamps,

if they are left on for more than 10 minutes after

the ignition is turned off. The cargo lamp shuts off

after 20 minutes. This prevents the battery from

running down.

 

but it also says the following on the next page under "Accessory Power Outlets":

 

Notice: Leaving electrical equipment plugged in for

an extended period of time while the vehicle is off

will drain the battery. Power is always supplied

to the outlets. Always unplug electrical equipment

when not in use

[6.2 GMC]

I also have that feature on my 2010 GMC. I didn't know this until I was playing the radio one cold winter morning with the engine off after only driving a short distance. I noticed a warning message on my dash telling me to start the truck to avoid a battery run down

[Beer Belly]

Ah ha !....thats why my radio shuts off while I'm sitting in my truck waiting for my Wife (truck not running)....seems to be after 20 minutes

[sno]

I can tell you for sure that neither my 2007 Sierra nor our (former) 2007 Suburban had "run-down protection" for the power points. Both vehicles have had their battery drained flat when the kids forgot to turn off their DVD player.

 

A pure mystery to me why GM would only protect against the interior lights and not all voltage draws.

[MS3DALE]

Ah ha !....thats why my radio shuts off while I'm sitting in my truck waiting for my Wife (truck not running)....seems to be after 20 minutes

 

Thats actually something different,Thats called "retained accessory power" or "RAP".....

 

Retained Accessory Power Description and Operation:

 

Retained Accessory Power (RAP)

The retained accessory power (RAP) system allows specific vehicle functions to operate for a specific amount of time after the ignition switch is turned OFF. The BCM monitors the ignition switch position, battery condition, and each door open/closed status to determine whether RAP should be initiated or terminated. RAP is controlled with 2 different methods; serial data and relay control. The relay is internal to the BCM and feeds multiple external components. Some modules receive a RAP message over the serial data circuits. Serial data controlled RAP is deactivated as required by their modules RAP power mode operation. Other subsystems are activated directly by the BCM through the internal RAP relay. Components and systems that are active in RAP are also activated anytime the ignition is any position other than OFF regardless of the door switch signals.

 

The BCM sends a serial data power mode message ending the RAP function when one of the following conditions are met:

 

• The BCM receives an input indicating the opening of any passenger compartment door after the ignition key is out of the ignition.

 

Important: The only door that will turn off the radio during RAP is the driver door. This is a function of the radio and will still turn off after the time limit.

 

• The BCM internal timer for RAP expires after approximately 10 minutes.

 

• The BCM detects a decrease in battery voltage below a calibrated limit.

 

Relay Control of Retained Accessory Power (RAP)

The body control module (BCM) keeps the internal RAP relay energized during all power modes, except Off-Awake and Crank. The relay is also energized for approximately 10 minutes after shutting the ignition OFF and removing the key, providing no door is opened. The BCM will de-energize the internal RAP relay at the same time the serial data message is sent to end RAP. When the internal RAP relay is energized voltage is applied on the accessory voltage circuit at BCM harness connector X2 terminal 22.

 

The devices powered by the internal RAP relay during the RAP power mode are as follows:

 

• Sunroof module - (CF5)

 

• Mobile radio fuse block, relay A - (9L4)

 

• Sliding rear window switch - (A48)

 

• Window switches, driver and passenger - (A31 w/o AN3)

 

Serial Data Control of Retained Accessory Power (RAP)

RAP systems controlled by serial data are as follows:

 

Power Windows:

If equipped with RPO AN3 the front window switches are separate modules that operate the windows on their respective side of the vehicle and receive the serial data RAP messages. Window RAP activation/termination timing is the same as relay operation.

 

Vehicle Communication Interface Module (VCIM) (Onstar®)

VCIM RAP activation/termination is the same as radio operation with 1 exception; if there is an active call when the ignition key is turned off the VCIM will remain in RAP mode and keep the radio in RAP mode until the call is terminated.

 

Radio:

Radio RAP activation/termination is the same as relay operation with 1 exception; the only door switch that will turn off the radio during RAP is the driver door open switch.

[deepstuff]

Will BRP shut off park lights if left on on a 2007 LTZ?

 

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[intheburbs]

Will BRP shut off park lights if left on on a 2007 LTZ?

 

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Yes, it will.

 

BRP basically disconnects most electrical systems after about 20 minutes if the computer senses a drain. Hazard lights are one of the few things BRP won't disable. If it's engaged, you won't even get interior lights when you open the door, but once you turn on the ignition, everything is back to normal.