Battery disconnected w/memory saver, then reconnected and now no power/start

[subkron]

I wanted to replace the battery heat shield (some critter got in there and made a mess) so I plugged in memory saver, disconnected battery, added new heat shield, reconnected same battery. I think memory saver collapsed to a low voltage. However, now there is no power - no response to fob (lock/unlock), no cranking, no interior lights, no headlights, etc. Hood light is on with hood raised. When I turn ignition the PRND display on rotary shifter flashes briefly.

As far as diags so far - battery measures 12.3V, checked both fuses (good) at positive terminal, took booster cable from battery terminal to 13mm nut on fuse box, pulled fuse F51 for 10 mins and re-inserted. Nothing at all, really, really dead.

Any ideas?

2015 1500 5.7L

 

[62Blazer]

Double check the battery connections/terminals are tight and you didn't accidentally damage or strain any of the cables. I have a 2016 and just replaced the battery this weekend. Just removed it, took the old one to the store and bought a new one, and reinstalled it. My clock was off and not sure about the radio station presets. But other than that no issues. Actually had the battery disconnecte twice. Installed it the first time and forgot to put the battery blanket on it so had to disconnect it again.

 

[subkron]

Wish it was that easy haha. I cleaned off the terminals before i snugged them up

 

[Wild one]

Wish it was that easy haha. I cleaned off the terminals before i snugged them up

At 12.3 your battery is down on juice a fair bit,but it should still start the truck,i agree with 62,start checking cables/battery posts etc.,as it's something you did causing your issues. You could try a battery disconnect "with-out" the battery maintainer and see what happens. My truck and the wifes Challengers plus my 300 all get the battery disconnected if they're gonna sit for more then a week,and i've never had any issue,only the clock and radio equalizer need resetting,the radio doen't even lose it's presets.
The battery maintainer might have caused you more issues then it cured

 

[subkron]

Went brute force and just pulled off negative terminal, went to lunch for an hour or so, came back and re-installed and all is - OK. I thought the memory saver would help to save time, but as @Wild one stated it probably "...caused more issues than it cured". Thanks

 

[Mando Mark]

I installed an Innovative Performance Chip in my 2019 Classic's 5.7L Hemi, and it recommended disconnecting the battery overnight for the computer to 'clear.' I did so and the only thing off was the clock wasn't correct, but the presets and all that were still in place when I reconnected it. I also replaced the battery last year and the only thing that goofed up was the clock.

 

[Wild one]

Went brute force and just pulled off negative terminal, went to lunch for an hour or so, came back and re-installed and all is - OK. I thought the memory saver would help to save time, but as @Wild one stated it probably "...caused more issues than it cured". Thanks

I'm not much of a fan of battery savers being used when you swap batteries or have one disconnected on a 4th Gen,they seem to cause more issues then they fix
My wifes 2019 Challenger was the drag oriented 1320 ,and it had to sit for about an hour with no key cycles,after reconnecting it's battery,before the drag pages would come back,and you had access to the line lock and transmission brake,but other then that,i've never had any issues disconnecting a battery on a Chryco product.
I used to always disconnect it's battery as soon as i got to the track,and step on the brake pedal/turn the headlights on for a couple minutes,then reconnect the battery,and by the time i had the street tires swapped for the drag radials,and the bugs/dust wiped off it,it was back to being ready to make track passes,the truck i never worried about,i'd disconnect it's battery,and as soon as it was reconnected the truck was ready to race.
I always disconnected the batteries on both at the track,so they would relearn the engine and transmission adaptives,and quite often between rounds i'd pulled fuses 29 and 32 on the car,so it started with fresh adaptives.
Lots of guys have shifting issues with their 1320's,and once they started pulling fuses 29 and 31 between rounds they never had shifting issues with their 1320's.The 1320's are an oddball as they're the only 6.4 Scatpack with a factory high stall convertor and factory transmission brake,and they seem to be prone to shifting issues after a couple passes.
I'm in the habit of disconnecting the battery on all my toys,then driving the hell out of them,so they relearn your driving habits,as the 8 speed has the capability of learning your driving habits,so a battery disconnect then a hard drive,sets the adaptives back to where i like them,lol