Got in the truck to head to work this morning, turned the key...both batteries dead. :'( Drove it yesterday and everything was just fine. I park it in the garage and have plugged her in the last couple of days since it has hit about 10 degrees over night. Checked to see if I left something on but can't find anything obvious? What could drain two batteries in 14 hours? Seems like only the fuel heat grid could draw enough or if all the lights were left on. Any other ideas? I plugged her into the charger and the batteries are certainly drained as it's pulling about 8 amps from the charger...so don't think it's a starter or silenoid problem. I hate electrical problems as they are usually so hard to track down. ???

 

Start removing fuses one at a time to help narrow it down

 

Looking at your profile.....I'd say let the dealer find it! You could measure the current in each circuit with DVM and narrow it down fairly quickly. As you say, to pull both batteries down within 14 hours, there has to be a pretty serious load happening. <br><br>On the other hand, a typical DVM may not be capable of handling that load without popping the internal fuse, so be careful if you decide to go that route.

 

Something else. A good way to to determine if it's the grid heater is to a) carefully feel the casting to see if it's hot (it should be if it's the culprit), or b) start your truck, and check to see if you headlights cycle up and down in brightness. If they do, it's probably means the grid heater system if working properly.

Oh, I see you pull. How about checking the &quot;always hot&quot; line on the round connector under the bumper to make sure there's nothing shorting it to ground.

-Tom-

 

Mine did that and it was the seat belt modual draining it.

 

Thanks guys for the advice. I'll follow your recommendations. I have over 36K on the truck so warranty is not an option and only would use the dealer as a last resort. It's a big draw so it has to be something obvious. Ramlovingvet - can you give more info on the seat belt module, where and how to check? I actually thought another possibility could be the seat heater staying on. That seems to be my wifes favorite option on the truck. I have yet to use them and the seats don't seem warm. Well, I'll be leaving work early to try and diagnose the problem. What else would I do on a Friday afternoon in 30 degree weather.

 

[quote author=Commatoze link=board=5;threadid=6492;start=0#60571 date=1036170779]<br>Something else. A good way to to determine if it's the grid heater is to a) carefully feel the casting to see if it's hot (it should be if it's the culprit), or b) start your truck, and check to see if you headlights cycle up and down in brightness. If they do, it's probably means the grid heater system if working properly.<br><br><br>-Tom-<br>[/quote]<br><br>Not sure if i'm reading this correctly but, is'nt the grid heater supposed to cycle if the truck is cold &amp; when the truck is running?<br><br>DRecu!

 

Something you might want to check would be your brake light switch. I have seen some that stick and the brake lights stay on all night and run the batteries down.<br>It would have to be something that draws some juice, I left the dome light on for 12 hours a couple weeks ago and it started right up like normal. Didnt even phase the batteries.<br><br>Keith

 

[quote author=drecu link=board=5;threadid=6492;start=0#60597 date=1036174398]
[quote author=Commatoze link=board=5;threadid=6492;start=0#60571 date=1036170779]
Something else. A good way to to determine if it's the grid heater is to a) carefully feel the casting to see if it's hot (it should be if it's the culprit), or b) start your truck, and check to see if you headlights cycle up and down in brightness. If they do, it's probably means the grid heater system if working properly.


-Tom-
[/quote]

Not sure if i'm reading this correctly but, is'nt the grid heater supposed to cycle if the truck is cold &amp; when the truck is running?

DRecu!
[/quote]

My point was, if the heaters are cycling properly, they could be discounted as the source of the problem. If the heaters are stuck on, the headlights will be dim, and the casting around the heater will be hot.

 

[quote author=ramlovingvet link=board=5;threadid=6492;start=0#60580 date=1036171905]<br>Mine did that and it was the seat belt modual draining it.<br>[/quote]<br>ditto

 

That's two votes for the seat belt module...I don't have a service manual so could someone point me to this mistery module...<br><br>Thanks, Jim

 

800 amp. hrs. capacity (guess) /14 hrs=57amp load. That must be one heck of a seat belt module!

 

No wonder my wife likes the truck so much. Maybe with the seat heater on and the seat belt plugged in she is getting more than just a warm seat? ;D

 

No wonder my wife likes the truck so much. Maybe with the seat heater on and the seat belt plugged in she is getting more than just a warm seat? <br><br><br>LMAO

 

Disconect both baterys from each other. Charge them sepurtly. You may have a dead battery or internily shorted battery,that would drain both batterys.Find a starter,alternater,rebuilder most towns have them.Autozone mite help as well.With dual batterys you lose one you stand a chanch to loose both.Have the batterys load checked.