Unfortunately truck still has the same battery drain problem, went for about a hours run today drove back home pulled in the driveway and shut it off, tried to start it again and the engine barely turned over , sigh
Removed the battery and now have it on the charger, so im back to square one ,Just hope the new alternator is not damaged.

I had a suspicion that something was wrong from day one when i first installed the new alternator, it was making a sorta whirring sound when the engine was running, It made that same sound just before the old alternator gave up.
Its like the alternator is working ovetime to supply power to something other than the battery .
Whats odd is that the truck was parked all night and started right up with no problems it only acted up when i got back from a hour drive ?
At this point im completly stumped.

 

Battery wouldnt drain while running unless the alternator isnt charging or the battery has a bad cell in it.

 

New battery installed just last summer and was stored away most in last winter as i didnt use the truck much, just had a new alternator installed , i dont want to spend another couple hundred for a new battery unless im 100% sure. I just then took the battery off the charger and re-installed it and the truck started right up no problem, checked the voltage its reading 14.4 volts which i think is normal ? and its still making that whirring sound which doesnt seam right to me because i know how the engine sounds when something is wrong.
Only thing a know to do is to go back to checking through the wiring harnesses again, unplugging two connectors on the BCM removes the battery drain problem , removing all the fuses does not make any difference.Its like only when the BCM is energized/activated that the drain problem occurs. Checked all the wires in connectors C2280D and C2280A with a ohmeter and found no shorts to ground, yet unplugging those two connectors removes the drain problem ?

 

New battery will still have warranty, so will the alternator.

 

Battery voltage is reading about 12.6 volts , alternator output is 14.4 volts , how do i know if the battery or alternator is bad , i dodnt want to just throw parts at it ? I no longer have the original receipt for the battery. Also when i leave the truck parked overnite it starts fine the next morning but when i take it for a run for an hour the battery runs down ?
With the engine off and the cable disconnected to the engine bay fuse panel my ammeter is reading an accessive current draw of around 6 amps and sometimes spiking to 12 or 16 amps on the cable going to the BCM panel in the cab ? Removing the fuses made no difference , checked all the wiring for shorts to ground but found nothing, its only when two connectors are unplugged that the problem goes away ?
Also when i disconnect the main + cable going to the BCM and test it with my ommeter it shows no shorts to ground, its like it only draws accessive current when the BCM is energized/activated ?

Is there anything else i can do or test ? I dont want to randomly unplug connectors from the BCM while the engine is running ?

 

I have a 4 amp draw on the battery with everything off. I had previously pulled every fuse and relay and still had the draw. I took it to the dealer and they said they would need the truck for 2 or 3 days so I declined and decided to search some more. I disconnected wire #3 in the photo and the draw stopped. I reconnected #3 and disconnected wires #1 and #2 and still had the draw so it's something fed through the fuse box. I disconnected radio fuses 32 and 33 at the interior fuse box and still have the draw. I would love to hear other ideas. I may need to put a switch in wire #3 so I can drive it until I figure this out.

 

I then called the person that repaired the alternator and he said 14.4 volts is normal for the charge across the battery , but he said he can do a load / test on my battery , will be dropping it off tomorrow , will post the results here when i get it back.

 

I wish I could find a shop that still does load testing.

 

4 amps is a lot of draw. Something like a starter solenoid sticking might draw that much or a radio amplifier on or lights, door lock relay, instrument cluster staying awake etc

 

Got the battery back today, tech said battery is fine, lots of cranking amps. Not sure if i should call that good news or bad news it this point. He said the problem could be the starter acting up intermittently , so my next pain in the butt is to remove the starter and get it looked at i dont know what else to do.
I just then put the battery back on the truck and it started right up fine no problems but i know for a fact if i take it out for a drive for a certain amount of time , park it , shut it off and try to re-start it will barely turn over and may or may not start ? /
/
Tech said it doesnt sound like there's a problem with the BCM because the truck isnt having any BCM related problems like flickering or intermittent lighting, random door locks or power windows .Everything in the truck works fine no issues .