Head off a problem - battery or starter?

[Coolmaker]

My neighbor's GMC had the same problem at 5 years. Replaced battery and all is good again. ;)

[Schmidty72]

Update:

Hey all - so I moved on to the fuses inside the car - and I had a problem with the power down delay that doug_scott mentioned (which I took into account previously - the truck sat for 4 hours, and the door was not opened prior to testing the fuses in the engine compartment). So, I couldn't figure out how to trick it into thinking the door was closed and as a result, I started pulling fuses and when I got a drop, I give it the time needed to get through the power down delay with the door closed. That was annoying enough to lose my helper (i.e., my wife), but I got through and in short, found .02 to .05 drops for at least three fuses (maybe a couple more, there were weird fluctuations and my helper wasn't sure if they were real drops or not):

 

PDM - (unsure at the moment what this is)

DDM - Driver door module

TBC 2B - Truck body controller

 

So, these are all things related to the power down that I may or may not have correctly tested.

 

Here is what I'm doing:

1. Unplugging the negative terminal at night

2. Pulled the radio fuse so if I stop somewhere I don't have as much draw down

3. Gonna buy a new battery

 

So - anyone have any thoughts if this is as I suggested above - either a bad ignition switch or bad Body Control Module? OR do I have 5 or 6 simultaneous failures in different systems? OR something else?

 

Also, having disconnected the battery during long rests, the volts are up to 12.4 (from 11. 9), I'm assuming that is a good thing.

[markw8]

Replace your battery then see if you still have a problem. Also, did you inspect the cables real good?

 

Mark

[Schmidty72]

Mark,

Did not inspect the cables other than at the terminals and they were good. I didn't do that once I found the draw and identified it as the radio, instrument panel, etc. Do you think I'm getting a head of myself?

Cheers,

Bob

[markw8]

At 6 years your battery is old. I would replace it and inspect and clean all your cable connections. I know this won't fix a potential draw problem, but it will take it out of play if there are other issues. It used to be if the cable end didn't go bad, the cable pretty much lasted the life of the truck. Not so much now.

 

Mark

[gmtech4]

looked it up for you to see that maybe you need to take it in before you talk yourself into replacing something expensive for no reason

 

 

Battery Electrical Drain/Parasitic Load Test

 

 

Tools Required

J 38758 Parasitic Draw Test Switch

Diagnostic Aids

 

 

• Rule out any possible obvious influences, such as customer error or aftermarket equipment.

 

 

 

• Check customer driving habits, such as regular short trips. This does not allow enough time to properly charge the battery. Refer to

Battery Description and Operation .

 

 

 

• Verify that the battery and charging system are in proper working order. Refer to

Battery Charging and Charging System Test .

 

 

 

• A battery discharging for no apparent reason while the vehicle is parked can be caused by an intermittent draw, such as a module waking up, or a continuous draw, such as a dome light or stuck relay.

 

 

 

• Some systems and modules such as OnStar®, and regulated voltage control (RVC), if equipped, are designed to wake-up, perform a task, and go back asleep at regular intervals. Refer to

Control Module References for the system or modules description and operation.

 

 

 

• Some systems and modules such as theft, or remote keyless entry (RKE) will wake up due to an outside input. Refer to

Control Module References for the system or modules description and operation.

 

 

 

Important: The battery specification listed below is a generic specification. Refer to chart when testing the battery.

 

 

 

• The battery run down time will vary depending on cold cranking amperage (CCA) and reserve capacity (RC). If the CCA and RC are higher, then the battery run down time would be longer. If the CCA and RC are lower, then the battery run down time would be shorter. The graph below indicates roughly how many days a 690?CCA battery with at 110 min. RC (60.5?AH) starting at 80?percent state of charge will last with a constant current draw until it reaches 50?percent state of charge. Differences in battery rating and temperature will affect the results.

 

 

 

Current Drain

 

 

 

Days

 

 

 

25?mA

 

 

30.5

 

 

50?mA

 

 

16.5

 

 

75?mA

 

 

11

 

 

100?mA

 

 

8.25

 

 

250?mA

 

 

3.3

 

 

500?mA

 

 

1.65

 

 

750?mA

 

 

1

 

 

1?A

 

 

0.8

 

 

2?A

 

 

0.4

 

<a href="http://gsi.xw.gm.com/newsi/showDoc.do?laborOpCode=&docSyskey=1583991&cellId=37588&pubObjSyskey=5090125&from=sm&pubCellSyskey=835987#N65907">

Load Test

Notice: Do not turn the parasitic draw test switch to the OFF position with the engine running. Damage will occur to the vehicle's electrical system. Notice: The test switch must be in the ON position when removing the fuses in order to maintain continuity in the electrical system. This avoids damaging the digital multimeter due to accidental overloading, such as a door being opened to change a fuse. Important: The test switch on the J 38758 is marked ON and OFF. When the test switch is in the ON position, the circuit is closed and electrical current will pass through the switch. When the test switch is in the OFF position, the circuit is open and electrical current will not pass through the switch.

Caution: Refer to Battery Disconnect Caution .

 

 

 

1. Disconnect the battery negative cable. Refer to

Battery Negative Cable Disconnection and Connection .

 

 

 

2. Install the male end of the

J 38758 to the battery ground terminal.

 

 

 

3. Turn the

J 38758 test switch to the OFF position.

 

 

 

4. Install the battery negative cable to the female end of the

J 38758 .

 

 

 

5. Turn the

J 38758 test switch to the ON position.

 

 

 

6. Road test the vehicle and activate ALL of the accessories, including the radio and air conditioning. This may take up to 30?minutes.

 

 

 

Important: Leaving the key in the ignition on some vehicles may cause a parasitic drain that is above the recommended amount. Refer to

Body Control System Description and Operation .

 

 

 

7. Park the vehicle. Turn the ignition switch to the OFF position and remove the ignition switch key.

 

 

 

8. Connect a 10-amp fused jumper wire to the test switch tool terminals.

 

 

 

9. Turn the

J 38758 test switch to the OFF position. The current now flows through the jumper wire.

 

 

 

10. Wait one?minute. If the fuse blows, install an inductive ammeter to locate the current draw.

 

 

 

11. Turn the test switch to ON and then remove the fused jumper wire.

 

 

 

12. Set a digital multimeter to the 10?A scale.

 

 

 

13. Connect the digital multimeter to the test switch tool terminals.

 

 

 

14. Turn the

J 38758 test switch to the OFF position. The current flows now through the digital multimeter.

 

 

 

15. Wait one?minute. Check and record the current reading.

 

 

 

 

15.1 When there is a current reading on 2?A or less, turn the

J 38758 test switch to the ON position. The electrical current will now pass through the switch.

 

 

 

 

15.2 Then switch the digital multimeter down to the 2?A scale for a more accurate reading when the

J 38758 test switch is turned OFF.

 

 

 

16. Turn the

J 38758 test switch to the OFF position. Wait 15?minutes for most vehicles.

 

 

 

17. Check and record the current reading.

 

 

 

18. Note the battery Reserve Capacity, amp hour rating. Refer to

Battery Usage .

 

 

 

 

18.1 Divide the reserve capacity by 4, amp hour rating by 2.4.

 

 

 

 

18.2 Compare this to the multimeter milliamp reading taken in the previous step. The parasitic current drain should not exceed this number. Example: If a battery has a reserve capacity of 100?minutes, (60?A/H) the current drain should not exceed 25?mA.

 

 

 

19. If excessive current drain is not found at this time and there are no other apparent causes, complete the following:

 

 

 

 

19.1 Using the MIN/MAX function of the digital multimeter, monitor the parasitic drain overnight or during the day. This will determine if something has been activated during that time frame.

 

 

Notice: The test switch must be in the ON position when removing the fuses in order to maintain continuity in the electrical system. This avoids damaging the digital multimeter due to accidental overloading, such as a door being opened to change a fuse.

 

Important: Removing fuses, relays, and connectors to determine the failure area may wake up modules. You must wait for these modules to go to sleep or use the sleep function on the scan tool.

 

 

 

19.2 When the vehicle has an unacceptable amount of parasitic current drain, remove each fuse one at a time until the current drain falls to an acceptable level. This will indicate which circuit is causing the drain. Refer to

Power Distribution Schematics to diagnose exactly which part of the suspect circuit is causing the parasitic drain. In some cases a non-fused circuit or component, such as a relay, is the cause of excessive parasitic current drain.

 

 

 

 

19.3 Repeat the parasitic current drain test procedure after any repair has been completed to make sure that the parasitic current drain is at an acceptable level.

 

 

 

 

19.4 When the cause of the excessive current drain has been located and repaired, remove the

J 38758 .

 

 

 

20. Connect the battery negative cable to the battery negative terminal.

 

 

[Schmidty72]

Thanks - that was helpful.