Well, I lost a laundry list of things on battery replacement!

[MrJeep]

Please help allay my fears.
Started to get the "battery low, Aux switches won't function" message for a few seconds on each startup this month. Figured I was at 4 years so that seems to be when the battery goes according to these forums and I was dying to do the aux delete anyway since I have the start/stop delete module.
Got a killer deal on black Friday Odyssey AGM94 from Napa ($90 off)
Followed the specific instructions not to let any connectors touch anything and electrical taped them with rubber gloves, etc. Pulled fuse 42 and taped off Aux ground. I'll pull out the aux battery when it gets warmer.
Now when I went in the Uconnect is in some kind of safe mode with a different color screen, you cannot adjust the temperature to anything, it just goes back to "LO" my backup camera is out, and the engine isn't idling perfectly like it was.
It seems like according to the internet everything might go back after a few hours/a day?

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[CrazyCooter]

It will probably come back to normal after a full sleep and reboot cycle. My first Odyssey battery was defective and then when I replaced it with an Easy Penn the following week, I had the HVAC and radio not work at first. Was good to go by days end. I even tried a full reboot w/ the Tazer with no luck at first.

 

[Mr._Bill]

Whenever the head unit is rebooted (full power loss), it can take up to 24 hours for normal operation to return.

 

[chorky]

I had this s well. Like Bill said for me it did take 24 hrs. I was in total freakout mode at first as I did accidentally ground a couple of the main buss wires by mistake. So far no indication of damage

 

[ShadowsPapa]

I was in total freakout mode at first as I did accidentally ground a couple of the main buss wires by mistake.

You are one of the last ones I'd expect to hear that from!

 

[chorky]

You are one of the last ones I'd expect to hear that from!

Yeah...I know :-( Got lucky. I was in a rush, and it was single digits when doing the work, so fingers were a little frozen. I should have just waited till it warmed up.

 

[legacy_etu]

Having to wait 24 hours to get your head unit and hvac working sounds pretty inconvenient . Can you at least still operate the hvac with the hard buttons?

 

[chorky]

Having to wait 24 hours to get your head unit and hvac working sounds pretty inconvenient . Can you at least still operate the hvac with the hard buttons?

for me, hvac stuff all worked just fine with the buttons. I usually keep mine in auto mode and it remembered the temperature setting - which is funny because everything else was weird. It acted like it was a brand new unit - no radio, no GPS, blank style background screen. It was annoying for sure, but it did go back to normal. The annoying thing is that probably happens every time you have to replace a battery.

 

[ShadowsPapa]

for me, hvac stuff all worked just fine with the buttons. I usually keep mine in auto mode and it remembered the temperature setting - which is funny because everything else was weird. It acted like it was a brand new unit - no radio, no GPS, blank style background screen. It was annoying for sure, but it did go back to normal. The annoying thing is that probably happens every time you have to replace a battery.

Unless you power the electronics during the battery swap......... there are systems for doing that.

 

[Volt0]

Unless you power the electronics during the battery swap......... there are systems for doing that.

What kind of black magic are you talking about? Do tell ..

 

[chorky]

Unless you power the electronics during the battery swap......... there are systems for doing that.

I suppose I was thinking in my situation with the genesis setup, since it's kinda a pain to get everything apart.

 

[legacy_etu]

for me, hvac stuff all worked just fine with the buttons. I usually keep mine in auto mode and it remembered the temperature setting - which is funny because everything else was weird. It acted like it was a brand new unit - no radio, no GPS, blank style background screen. It was annoying for sure, but it did go back to normal. The annoying thing is that probably happens every time you have to replace a battery.

Well that’s good. I was thinking about having to deal potentially with no heat for 24 hours if you swapped your batteries in the winter.

 

[Mr._Bill]

If you have good cellular service, especially in an AT&T area, it seems to recover faster. Part of the recovery appears to be validation with and some downloads from the mother ship. When I replaced my Aux battery, recently, the head unit was back to normal by the time I was ready to start it up and check everything.

 

[MrJeep]

Well that’s good. I was thinking about having to deal potentially with no heat for 24 hours if you swapped your batteries in the winter.

This was my biggest concern. The ac being stuck on LO while it is so cold here.

Thanks, all!
Everything came back 3 hours later. Crazy. I thought for sure I was headed to the dealer.

 

[ShadowsPapa]

If you have good cellular service, especially in an AT&T area, it seems to recover faster. Part of the recovery appears to be validation with and some downloads from the mother ship. When I replaced my Aux battery, recently, the head unit was back to normal by the time I was ready to start it up and check everything.

Yeah, in my case, I'd need to drive into town near a cell tower and park it.
The Jeep can't be found in our garage - I can take and make calls in there with my cell phone but that's USCC and they cover rural Iowa better than ANY other cell service (I proved that to my boss when working IT - so they started switching the problem area offices to USCC away from the others)

What kind of black magic are you talking about? Do tell ..

Anyway, for not losing settings - there are devices that literally plug into the OBD port or lighter socket (12v outlet- assuming it's always live) for just this type of things in other cars and trucks. But we don't have live 12v outlets and I've not tried using the OBD port to keep things alive.
There are commercial devices called something like "settings savers" or whatever.
If you want, you can make your own using a very small 12v battery like those used in trailer electric brake disconnect systems (the ones that power the trailer brakes in event of a break-away)
You don't want something really high amperage - anything that can supply 12 volts and an amp or two should work. Some battery maintainers even have such a setting! Power supply mode............
Then you can rig a connection into the trailer connector hot and ground pins, or, clip to post N2 on the PDC, and a ground away from where you are working.
Then you can swap out the batteries, being extremely careful to keep all terminals away from anything else at all - like each other, grounds or whatever, because the truck's wiring systems will still be hot, even with the batteries disconnected.
It doesn't take much to keep the systems powered.

Tip - do the work with the key FOB in the house, well away from the truck, and wait roughly 30 minutes after driving it to start the process - I think I read somewhere, that things stay awake for a while, then later some go into a sleep mode after no activity and no approaches with a FOB in hand. @Hootbro can correct me if wrong on that.

In any case, the keeping the FOB away is valid as it's going to want to stay alive and draw more power, maybe even turning on the cluster/radio and headlights if you get near with a FOB while swapping batteries with an auxiliary power supply keeping things alive.

If you power things via the trailer connector you have the safety of the 35 amp fuse that hopefully would blow should you make a boo-boo while swapping batteries on a powered system. If you go through N2 and ground under the hood - be careful - there's no fused protection should you bump things together that should not be bumped together while powered up.

So you could use a commercial "settings saver", or a battery tender/maintainer or small charger that has a power supply setting, and you can go through any spot that has ground and connection to the main bus - like the high current fuse array bus.

Or, you can wait 24 hours.

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