03" Draining battery ??
Last night I pulled the battery and ran it in my truck for about an hour, this morning the truck started fine, so this morning I took the battery and had it checked anyway hoping it was bad, but it tested good. When I connect the battery up I get a small arc or bite. One by one I pulled the fuses and relays next to the battery to see it the arc stopped, no difference.
The only electrical add on was an IPOD to car that I installed 6 months ago. Anyone have any ideas? I am at my skill levels end; next stop would be to take to GM with keys in one hand and Vaseline in the other.
Thanks,
I agree with checking the power seat switches. I had this problem off and on for about a year and found the problem by dumb luck: I just happened to touch the top of my driver's side sun visor and found the plastic door that covers the mirror was warm...and the car had not been driven in a day. It turned out that the cover wasn't pushing the button down far enough to turn the mirror lights off. All I did was tape a quarter on the back side of the cover so it would push the switch down far enough to keep the lights off. I didn't feel like putting the effort into taking the visor apart to fix it since I don't use the mirror anyway. All it cost me was 25 cents....
I don't read the General board often enough and this info about the Ipod setup is very interesting. I don't have one in my car but had been giving it some thought. The way the battery in my Ipod is always run down, I'd probably be draining the Vette battery just to keep the poor battery in the Ipod charged.
In my case it didn't have anything to do with charging the iPod. The Peripheral would still draw current even with the iPod unattached. I never left my iPod in the car. I did the current draw test and found the ipod2car Peripheral to be the culprit. Since it has been disconnected I have had no problems with battery drain.
If I had been driving my car daily, I probably would not have noticed. The original poster said his battery would drain overnight which would make me think that there may be something besides the ipod2car that is adding to his problem.
My car would have to sit for several days to drain low enough to not start the engine.
What is # 25? Does it control the entire fuse box in the foot well? Should I leave that fuse in and continue pulling fuses?. I worked from the bottom up, so I had about 15 more to go…..
Thanks,
Rick
What is # 25? Does it control the entire fuse box in the foot well? Should I leave that fuse in and continue pulling fuses?. I worked from the bottom up, so I had about 15 more to go…..
Thanks,
Rick
Fuse #25 powers the BCM and the Instrument Panel Cluster.
A small arc is typical when connecting the battery back up.
The draw without 25 in is normal. Something that the Bcm 1 is controlling is the culprit.
You need to reinstall fuse 25, and do the rest of them in all the fuse blocks, to find the culprit.
Some of the usual suspects have been the Vanity mirrors not shutting off, check in a dark garage or at night and look for a light on either at the vanity mirrors, the rear view mirror inside lights, the glove box light, or trunk and underhood light. Also the seat motors including the lumbar motors can go on intermittently all night. The door locks if you have the passive fobs can be activating if the fob is close enough.
Good Luck
Last edited by bestvettever; Aug 6, 2008 at 12:03 AM.
I then pulled all the relays in the foot well, no change with a steady 6 3 amps draw, then I pulled all fuses, zero draw, reinstalled # 25 and had a steady 1.8 amps draw.
Inserted each fuse one by one, several fuses added .1 to .6 amps of draw. I disregarded these and found # 5 pulling 1.4 amps and # 29 pulling about the same. I waited with everything closed with #’s 5 & 29 pulled for the car to go to sleep, but never saw it drop below 1.8 amps. I also tried 5 & 29 individually. Part of my problem seems to be that the car won’t go to sleep
I have a decent skill level in troubleshooting current draw, mostly in a AC to DC network, but this is getting tricky, the Vaseline is looking pretty good about now…. Unless the experts here can read between what I have troubleshot..…
Thanks,
Rick
PS. the yellow 03' in my sig. is gone, this car is a spiral grey 03' 6-speed vert. Maybe this changes something.....LOL
As long as something is drawing current the car will not go to sleep.
Good Luck
Last edited by bestvettever; Aug 7, 2008 at 11:59 PM.
The Best of Corvette for Corvette Enthusiasts
SEE Below
++++++++++++++++++++++++++++++++++
Body Control System Description and Operation
This vehicle is equipped with a Body Control Module (BCM) capable of performing multiple body control functions. The BCM, which is the power mode master, is responsible for sending the power mode messages on the serial data line to other systems.
Serial Data Power Mode
On vehicles that have several control modules connected by serial data circuits, one module is the power mode master (PMM). On this vehicle the PMM is the Body Control Module (BCM). The PMM receives two signals/circuits from the ignition switch. These are the Ignition 1 and Ignition 2 ignition switch signals/circuits.
To determine the correct power mode the PMM uses:
The state of these signals/circuits, either switch closed (B+ = 1) or switch open (B+ = 0)
The sequence of switch closures received by the PMM
The status of the engine run flag
The chart below indicates the modes detected and transmitted by the PMM:
Correct Ignition Switch Inputs Power Mode Selected/Expected
Engine Run Flag Serial Data
Sampled Ignition Signal State
Power Mode State
Key-In Sense
Ignition 1
Ignition 2
OFF
0
0
0
OFF-AWAKE
NA
RAP
0
0
1-0
RAP
NA
UNLOCK
0
0
0-1
UNLOCK
NA
ACCESSORY
0
0
1
ACCESSORY
NA
RUN
1
1
1
RUN
NA
RUN
0
1
1
RUN
NA
CRANK
0
1
1-0
CRANK
NA
Fail-safe Operation
Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the PMM fail to send a power mode message. The fail-safe plan covers those modules using exclusively serial data control of power mode as well as those modules with discrete ignition signal inputs.
Serial Data Messages
The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid PMM message until they can check for the engine run flag status on the serial data circuits. If the PMM fails, the modules monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is True, indicating that the engine is running, the modules fail-safe to "RUN". In this state the modules and their subsystems can support all operator requirements. If the engine run flag serial data is False, indicating that the engine is not running, the modules fail-safe to "OFF-AWAKE". In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
On this vehicle the following modules receive Serial Data Messages for power mode status:
Driver Door Module (DDM)
Passenger Door Module (PDM)
Radio
Discrete Ignition Signals
Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid PMM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, B+, the modules will fail-safe to the "RUN" power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to "OFF-AWAKE". In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
BCM Wake-up/Sleep States
The BCM is able to control or perform all of the BCM functions in the wake-up state. The BCM enters the sleep state when active control or monitoring of system functions has stopped, and the BCM has become idle again. The BCM must detect certain wake-up inputs before entering the wake-up state. The BCM monitors for these inputs during the sleep state, where the BCM is able to detect switch transitions that cause the BCM to wake-up when activated or deactivated. Multiple switch inputs are needed in order to sense both the insertion of the ignition key and the power mode requested. This would allow the BCM to enter a sleep state when the key is IN or OUT of the ignition.
The BCM will enter a wake-up state if any of the following wake-up inputs are detected:
Any activity on the serial data line
Hatch ajar switch
Hatch release switch
Door ajar switch
Key-in-ignition switch
Monitored load relay
Park/fog/headlamps are on
The BCM experiences a battery disconnect and reconnect condition.
The ignition is turned ON.
The BCM will enter a sleep state when all of the following conditions exist:
No activity exists on the serial data line.
The ignition switch is OFF.
No outputs are commanded.
No delay timers are actively counting.
No wake-up inputs are present.
If all these conditions are met the BCM will enter a low power or sleep condition. This condition indicates that the BCM, which is the power mode master of the vehicle, has sent an OFF-ASLEEP message to the other systems on the serial data line.
Power Requirements
The BCM has two main power feeds (high and low current), and two main grounds. The low power feed (battery 1) is used to provide power for the BCMs logic and internal driver operation. The high power feed (battery 2) is used to provide power for systems that draw higher amounts of current (motors, lights, etc.). The BCM will operate properly with a system voltage of 9.0-16.0 volts. If system voltages exceed 16.0 volts the BCM will provide protection by disabling certain functions that may be damaged due to higher than normal system voltages.
Monitored Loads
In order to minimize any battery rundown, the BCM can detect if certain electrical loads have been left ON after the ignition is turned OFF and the driver has left the vehicle. When the BCM detects that the ignition has been cycled to the OFF position, the BCM immediately checks the status of the load monitor input. If the BCM detects that a load is present (grounded input), the BCM turns ON the load monitor relay for 15 minutes. If after 15 minutes the BCM still recognizes that a load is present, the BCM will turn OFF the relay, removing the battery voltage from the loads. The BCM continues to monitor this circuit for a switch transition. The BCM will again turn ON the relay for 15 minutes if a switch transition occurs.
Load Shed Control
The BCM can turn off the rear window defogger and heated outside mirror electrical loads when the vehicle is in a condition where these loads may discharge the battery. The BCM will also remove these loads when engine demands are greater.
Interior Lamp Over Voltage Protection
The BCM disables the interior lamp bulbs when the system voltage is above 18.0 volts in order to extend the bulb life.
Driver in Vehicle Detection
Using the ignition switch/door ajar inputs, the BCM can detect whether or not the driver has left the vehicle. If the ignition is turned to OFF with no door ajar status detected, the BCM assumes that the driver is in the vehicle. As soon as the BCM detects a door ajar, the BCM will assume the driver has left the vehicle. The BCM uses this information to determine the RAP status, then sends the status to the other systems also responsible for RAP functions.
BCM Fail-Soft Condition
If a particular BCM malfunction would result in unacceptable system operation, the BCM takes a fail-soft action in order to minimize the condition. A typical fail-soft action would be the substitution of a fixed input or output value when the BCM is unable to interpret data correctly.
I could state here something to the affect that a firefly was trapped between the front headlight and the socket connector, drawing current as it lit up, or something else wild as such…..but, I must man up, only to keep a fellow vette owner from wasting 4 hours of their life as I did.
Hand me the forum’s idiot hat, dumb *** award (can you say *** here?) or other moniker, but the entire issue was the gauge cluster **** was on…..not on the dash, or the console….just plain on.

My troubleshooting led me to 4 fuses pulling various draws from .2 to 1.6 amps totaling 6.3 amps of draw. I could never get the car to sleep because the the draw was coming from the fuse you need inserted to look for the culprit.
I make this admission and add, if you have over .3 amps of draw with only fuse # 25 in the foot well fuse box inserted, go turn the #$%^&%# cluster switch off !!!
That’s it, I’m out, I’m going to curl up with a bottle of crown and ask the gods of horsepower for forgiveness……….
Thanks, Rick
PS. I’m almost out of gas, how do you get the fuel door open ?
good luck. you sound like you know what you are doing which was more than me!
whoops, i just read the you found the cluster switch on. never mind
Last edited by bluvette79; Aug 9, 2008 at 06:35 PM.
When I had the battery checked, it was far from being fully charged, in fact I was worried that they would want to charge it first before testing it.
Since the install of the Ipod to car 6 months ago, I have gone up to 3 week weeks without running the car with no issues seen, I have never gone over 3 weeks without running the car. Is this harming the battery, i don't know?
I stopped leaving it plugged in and the problem went away, I can leave the car sit for weeks and restart with no issues..
Zach













