Batteries won't work

It is possible you are using the wrong type of battery. A lot of electronics require you to use either Lithium-Ion or less powerful ones. I had this happen once by putting in batteries that were the right size, but were meant for more powerful devices. If you have a cheap set of the right size batteries laying around that are a different type, try those.

scale won't weight after resetting.

see this causes and proceed . God bless you
If the camera won't turn on, check the batteries, or connect the camera to an AC adapter. If that doesn't work, remove all batteries, disconnect the AC adapter, wait a minute, reinsert batteries and reconnect the adapter.
If the flash doesn't work, the camera won't take pictures, or the screen keeps turning off, check that the batteries are strong.

Clear the codes AFTER a repair was made & the light
stayed on ?

I would purchase an inexpensive $60.00 code reader &
use that.

If you start disconnecting batteries on every vehicle you
do or will own,then bad things happen.

The radio won't work,the car won't start,etc

If you have service manuals to learn your vehicles systems,
then you can eventually know what the results will be

Again,if you fixed nothing,then the light is going to stay on
or come back

un hook your battery for 15 minutes then retry to start

Replace the battery pack with new one. It has damaged.

Battery could be dead and won't hold another charge. Batteries only last for so long until you have to replace them. If you laptop is ok with the AC Adapter & Power Cord meaning it boots and allows you to work in windows, then the battery is definitely dead.

Sometimes, the lower contacts get bent downward after years of use, causing the batteries to ride low in the compartment, and thus making poor contact when the battery door is closed. Try lifting/bending these interior battery contacts upward, so that the batteries ride higher when inserted.

Sounds like the receiver portion of your logic board has quit. The wall control is hardwired and doesn't use the receiver.

I assume you have put fresh batteries in these... ONLY use good quality Alkaline batteries. The Re-chargeables will not work.