Helping out my FIL since his truck was dead as a doornail in his garage. Story is the battery died during a trip to the store, AAA came and replaced it with a new battery. Worked for a while, but he didn't drive it for a month. Wife tells me it won't start, so I load up my tools and find out it's not just weak, it's quite dead at 3 volts. Tried throwing the charger on it, but it seems to have lost a cell because it would not charge over 11.5 volts. Put a new battery in it, and the alternator is charging normally, but a quick check shows it pulls about 1 amp for 15 seconds after connecting the battery, then drops to 180 mA. That seems rather high, my Pilot just had a dead battery episode, and that pulls about 50 mA of idle current. Any idea what's normal for his truck? Can't find anything obvious like an interior light left on, but my math tells me that 180 mA for 30 days would be 129.6 amp-hours, way beyond a typical 80 amp-hour battery.
2004 GMC Sierra 1500 idle current
- Thread starter Dave Sherman
- Start date
Seems high to me. 2004, might it have RKE?
I would start pulling fuses... one of them is going to give good idea what circuit its on.
I have to wonder if the "new" battery was fully charged when installed. I usually can drop one in and go, but for me, a short drive is 30 minutes, and it's normal for me to drive an hour at a time, twice a day, so a not so full battery will likely get there quickly. Lightly used vehicle, I have to think, hooking up a smart charger is wise.
I would start pulling fuses... one of them is going to give good idea what circuit its on.
I have to wonder if the "new" battery was fully charged when installed. I usually can drop one in and go, but for me, a short drive is 30 minutes, and it's normal for me to drive an hour at a time, twice a day, so a not so full battery will likely get there quickly. Lightly used vehicle, I have to think, hooking up a smart charger is wise.
Hmm... Searching the interwebs is bringing up service bulletins about body control modules running the battery down, but also something about a light under the hood. Maybe I was measuring the light, but apparently the gravity switch can get sticky with rust. Also finding info that it can take 15-20 minutes for the thing to finally shut down, so I might have to do some longer term measuring.
Do you know how long it is using 180 mA? I don't know about the truck but when I had a problem with my BMW it had several steps to the current reduction before settling at a lower value. IIRC it took over a minute.
Edit, sorry I see you read that elsewhere.
I finally worked out the parasitic drains in my 08 Silverado. Turns out someone switched doors (?) and cut the wires in the hinge. Even if you know the history of this truck, the wires might have metal-fatigued themselves "cut". Anyway the truck never knew the driver left, via the door latch switch, so it kept the radio on, lights on, etc.
Ah, thank you for reminding me. My 2010 Traverse would occasionally not turn things off when opening the door because of a flaky door switch. I didn't see his interior lights turn on when opening the door, that might be a clue.
A typical spec is for a maximum of 50 mA. My car has this spec, but only measures 10 mA. 180 mA is excessive.
Some GM trucks have hood latch sensors that they use for under-hood lights or something. It could be that once the hood is closed the load would go down a lot. If this truck has a sensor, run some wires from the battery to outside of the vehicle and then close the hood. Also, the body management computer could take a while to go into sleep mode. Keep the meter connected for at least several minutes to see if the current eventually drops further.
If the reading is still high, start pulling fuses until the current drops to see which circuit the load is coming from.
Some GM trucks have hood latch sensors that they use for under-hood lights or something. It could be that once the hood is closed the load would go down a lot. If this truck has a sensor, run some wires from the battery to outside of the vehicle and then close the hood. Also, the body management computer could take a while to go into sleep mode. Keep the meter connected for at least several minutes to see if the current eventually drops further.
If the reading is still high, start pulling fuses until the current drops to see which circuit the load is coming from.
Update: So it turns out he had a rodent that made a mess of the fuse box. New fuse box, and it's back in business.
