Engine/Transmission (1998.5 - 2002) Electric problem

[CESpitz]

Does any body know how many amps the computer and radio and anything else that might be on draw when the ign. is off
I have a slow drain on the battery on a 01 that is being a pain in the neck. Any help would be very much appreciated.

 

[Road Dog]

There are a thousand ways to draw down the battery. Could be a faulty glove box switch. Could be a faulty seat belt controller. Hook up an amp metre and start pulling fuses.

 

[K5IP]

If you have a dc milliamp meter, I would disconnect both negative battery leads. Then place the meter in series with only one battery lead, and reconnect to the battery and measure the ambient current flow. I would expect it to be less than 1 amp. If much higher, start removing fuses until the drain goes away. That should get you in the ball park. If you do not have a milliamp meter, a small 12v light bulb could be used in place of the meter. If the bulb lights brightly, more than an amp of drain is occurring.
Rog

 

[CESpitz]

Thanks for the suggestion I have used the amp test and it has a .30 amp draw the batteries are new 1 mo. old but if the truck sits for 10 to14 days
it will not turn over. I was wondering if one of the new batteries could be bad. Thanks for the help.

 

[K5IP]

I think you are on the right track.
The next thing I would try is disconnecting both battery grounds and allow them (the batteries) to sit overnight (or a few days if possible). Then, measure the open circuit battery voltage of each battery. If one is appreciably lower than the other, you found your problem.
Rog

 

[CESpitz]

Thanks everybody I went out and pulled the grounds and will check in a few days

Thanks

 

[Road Dog]

Thanks for the suggestion I have used the amp test and it has a .30 amp draw the batteries are new 1 mo. old but if the truck sits for 10 to14 days
it will not turn over. I was wondering if one of the new batteries could be bad. Thanks for the help.

0.3A = 8AHr per day. Each battery is around 80AHr so it's a significant draw. Make sure the hood light is unplugged so you're not measuring that.

 

[K5IP]

CESpitz,
Just for grins, I disconnected the battery cables on my 03 and checked the drain. An ammeter was placed in series with one battery and at first, I thought I had more drain than you do. It measured .78 Amps, but then after waiting about a half a minute, it suddenly dropped to about .01 Amps. Guess something gets fired up when batteries are first connected. .
I know my truck is not the same as yours, but as others have suggested, I now believe you have significant drain.
Rog

 

[Road Dog]

It's called POST - Power On Self Test. On power up any computer runs a set of diagnostics and and then waits for something to happen. After a while it goes to sleep (low power mode) which is different than turned off.

 

[Bob4x4]

.3 is too high. Typically 3-7 milliamperes is in the norm once the controllers go to sleep.

 

[CESpitz]

How long does it take before they go to sleep from the time you turn of the ign.Thank you everybody for your suggestion it all helps

 

[Bob4x4]

Verify that all electrical accessories are off. Turn off all lamps, remove the ignition key, and close all doors. If the vehicle is equipped with an illuminated entry system or an electronically tuned radio, allow the electronic timer function of these systems to automatically shut off (time out). This may take up to three minutes. See the Electronic Module Ignition-Off Draw Table for more information.
ELECTRONIC MODULE IGNITION-OFF DRAW (IOD) TABLE
Module
Time Out?

(If Yes, Interval And Wake-Up Input)

IOD IOD After Time Out
Radio No 1 to 3 milliamperes N/A
Audio Power Amplifier No up to 1 milliampere N/A
Central Timer Module (CTM) No 4.75 milliamperes (max.) N/A
Powertrain Control Module (PCM) No 0.95 milliampere N/A
ElectroMechanical Instrument Cluster (EMIC) No 0.44 milliampere N/A
Combination Flasher No 0.08 milliampere N/A