Battery drain in cold weather

[PaulStern]

Battery is completely dead after the truck sits in cold weather for more than 48 hours. Dealer changed out battery, but it happened again. There has to be a drain on the battery some where. Possibly the seat heaters? Dealer does not want to replace the modules unless they know for sure that’s the issue.

[Transient]

AC Delco batteries?  I've had issues with them in the past.  In fact, just helped a woman with a 17 Acadia last week by jump starting her car because the AC Delco battery went bad.  Personally, there are times when my truck goes for days without being started.  When I go out to start it and drive I don't have any issues, however knowing my history with AC Delco batteries is only a matter of time.

[WeGone]

Not as cold as some of you deal with.

 

Mine sits several weeks outside under carport winter temps 40s days low 30s nite no issues.

Edited January 14, 2022 by WeGone

[redwngr]

There is a step-by-step diagnostic procedure determine if the source of the increased parasitic loss. 

 

Clearly it shouldn't be dead after 48 hours. 

 

 

Anything been added / plugged in that is causing additional drain?

[PaulStern]

It is not the brand of battery. This has happened 2 winters in a row in below freezing. The dealer has done diagnostics and can’t find the issue. We are on at least the third battery. The truck was totally dead and could not be jumped. 

[Supreme Pizza]

The way to determine of the battery itself is the problem, is to disconnect the negative battery post, and let it sit in cold weather for a few days. If the battery is dead, then the battery is the problem. If the battery is not dead, than there is a parasitic drain.

[Kilgore Trout]

Personally, if my dealer couldn't diagnose it, I would find another shop.  Parasitic drain can be challenging to nail down, but a competent shop will find it.

[EddDe]

On 1/14/2022 at 11:28 AM, PaulStern said:

Battery is completely dead after the truck sits in cold weather for more than 48 hours. Dealer changed out battery, but it happened again. There has to be a drain on the battery some where. Possibly the seat heaters? Dealer does not want to replace the modules unless they know for sure that’s the issue.

Do you leave anything plugged into the round 12v accessory power outlets (front and back) when truck is off, like a dash cam? My manual says these outlets are part of the "Retained Accessory Power (RAP)" and outlet power will turn off when truck is shut off and driver's door is opened. However, my outlets were always on and I found that the power outlets fuse F27 on my new 2020 Silverado was not in the correct position for RAP. In the Instrument Panel Fuse Block Right (access by opening passenger front door), check 50 amp fuse F27. Make sure this fuse is NOT connected with the lug at position F28. For RAP, F27 should be on the left and center lugs. Connecting F27 with F28 gives constant battery power, not RAP. 

F27 Accessory power outlet/retained accessory power
F28 Accessory power outlet/Battery

[Transient]

On 1/14/2022 at 5:11 PM, PaulStern said:

It is not the brand of battery. This has happened 2 winters in a row in below freezing. The dealer has done diagnostics and can’t find the issue. We are on at least the third battery. The truck was totally dead and could not be jumped. 

Same brand battery, or 3 different brands?  I've seen it before.  Once the original battery in the vehicle dies I swap out for another brand.

[Sdahl123]

Did you find the issue Paul?

[redwngr]

48 minutes ago, Sdahl123 said:

Did you find the issue Paul?

[salmonella25]

My Buddy is currently experiencing this issue. Dealer couldn’t find anything. Then they came back and said that the Power Seat Memory Circuit is drawing around an Amp of current when it gets below 40C…I find it hard to believe but will find out soon enough.

[Glava2876]

I have a 2020 with the 6.2. My other vehicles are in the garage, so the GMC lives outside. I’m retired so the truck can sit for days. Never had a problem in the cold with the original battery, but replaced it with another AC Delco battery in the fall because of age.

i live near Syracuse in central Ny and have a camp up near Ogdensburg NY. This winter we have regularly been having temperatures between 0-20 especially at night. 
I have had no starting problems at all. So there must be something drawing your battery down, especially if you’ve replaced it

 

[redwngr]

On 1/30/2025 at 10:26 PM, salmonella25 said:

My Buddy is currently experiencing this issue. Dealer couldn’t find anything. Then they came back and said that the Power Seat Memory Circuit is drawing around an Amp of current when it gets below 40C…I find it hard to believe but will find out soon enough.

 

Might be the issue. 

It's a known problem on some

 

(but is when below 40F (or 4C)

 

https://gm-techlink.com/?p=13299

Intermittent Parasitic Battery Draw Below 40° F/4° C

June 16, 2020

Several intermittent conditions related to a low battery state of charge may be found on some 2018-2019 ATS, CTS, XTS, Corvette; 2018-2020 Envision, LaCrosse, CT6, Escalade, XT5, Equinox, Impala, Malibu, Camaro, Silverado, Suburban, Tahoe, Traverse, Acadia, Sierra, Terrain, Yukon; 2019-2020 XT4, Blazer; and 2020 XT6 models.

The following low battery charge conditions may be present when the ambient air temperature is below 40° F/4° C for an extended period of time:

• Dead battery/required jump start
• Slow crank
• Battery low state of charge and, if equipped, Auto Stop/Start inoperative
• Instrument cluster backlighting turning on intermittently while the vehicle should be asleep
• Keyless or passive entry/start inoperative

These conditions are not easily duplicated in the service bay or in temperatures above 40° F/4° C.

These conditions may be due to a low battery state of charge that is being caused by one or more modules waking up the Low Speed GM LAN Bus. When the ambient air temperature is below 40° F/4° C, the Seat Memory Control Module (SMCM) could inadvertently wake up the Low Speed GM LAN Bus. All SMCM’s on a vehicle, including the Driver K40 (Fig. 9), Passenger K40P, Left Rear K40LR and/or Right Rear K40RR module, may apply.

Fig. 9

Begin diagnosis by asking the customer or inspecting the vehicle for any aftermarket equipment. If no aftermarket equipment is installed, try to duplicate the conditions by leaving the vehicle outside overnight in temperatures below 40 F/4 C.

Follow the Battery Electrical Drain/Parasitic Load Test procedure in the appropriate Service Information. If an excessive battery draw is duplicated, as part of the Circuit/System Testing procedure, remove the fuse(s) that powers the SMCM. The SMCM may be powered by more than one fuse. Wait several minutes to see if the vehicle will return to an acceptable battery draw level. If so, replace the appropriate SMCM.

If the battery draw does not return to an acceptable level with the SMCM fuse(s) removed, then continue with the diagnostic procedures in the Service Information.

Edited February 2, 2025 by redwngr

[Bobotsa]

On 1/30/2025 at 10:26 PM, salmonella25 said:

My Buddy is currently experiencing this issue. Dealer couldn’t find anything. Then they came back and said that the Power Seat Memory Circuit is drawing around an Amp of current when it gets below 40C…I find it hard to believe but will find out soon enough.

Any luck?