Ditto title

my truck has a brand new battery and drains it rapidly but only in cold weather

any ideas what causes this?

it’s rock solid in the summer but has a short in cold weather

 

Pull fuses until you find the circuit causing the drain,

 

in this case it takes 1-2 days to drain down.

with an ammeter in tow and a rapid charger I get 15 seconds of a pumping sound after attaching the charger and high amps
after things calm down (about a minute) the drain drops to near zero

This behavior appears to occur even with nearly every fuse removed.

the PO had an after market remote starter, not sure how to remove that thing if it failed but sucks since it must be right on the mains

 

Pretty much the way to troubleshoot it. On the top of my head I can't come up with anything causing the pumping sound but if it only lasts 15 seconds that should not be causing the battery go dead, unless it repeats in intervals. "Near zero" is relative, what numbers are you seeing ? Typically a "sleeping" vehicle is somewhere around 0.025A and if the draw is more than 0.1A there is definitely something wrong. I'd take the wiring diagram and pull pretty much every fuse shown. Also trace any aftermarket wiring.

 

Just because it's new doesn't mean it's good! Also is your truck charging properly? Have the battery load tested. If it is a parasitic drain this is how you test for it...

 

yep the battery is junk 13 volts but no amperage open cell), got a couple days from it
put a different battery in now my 4 ways run all the time and if I turn on the ignition the dash flashes, (let alone try to crank)
I’m gonna make sure the battery cable on the truck itself isn’t junk and the grounds are good.

hopefully something isn’t burned out, immediately before getting the new battery everything charged right up to proper voltages

Not sure what else might be going on, very strange

 

The grounds are a great place to start. You may just want to replace the battery cables. They do get corrosion inside from the ends over time. I replaced the cable to the alternator also. Clean the main connections in the under hood power distribution box also.

 

Well cleaned the grounds, replaced the positive and the truck starts, runs drives normally

BUT

The 4 ways can’t be shut off, even removing the fuses they keep running constant, how can they run with the fuses pulled?

also while the 4 ways flash the odometer flashes
Unless I turn the headlights

 

Somewhere they are getting power

 

removed the flasher module and the clicking and flashing lights continues so something else is going on