Just replaced the battery and it doesn't work...any advise?

you may have a air lock if you did all that work and it is overheating-thermostat ok?

Test your thermal fuses for continuity with a meter

if the batteries are new and the battery terminals are clean and not corroded or broken, and the battery polarity is correct when they were installed. There must be a fault in the internal circuits of the scale, and a technician with the right tools, training, and experience will be needed to repair it.
Maybe time for a new scale.

Under the battery tray is a common ground point. It'll have several black wires going to a connector that is bolted to the frame. Remove this bolt, clean the area up, and bolt it back in place. If the speedometer doesn't work after this, then you probably need a vehicle speed sensor VSS.

Have you checked your battery on the mouse? I would pressume that it uses battery since its wireless. Does it have a on/off switch? Because for it to work you need to turn it on. Can you post the exact model and specs of your wireless mouse? For us to better understand what were dealing with. Reply back. Good Day.

check for a shorted switch under the pedal , its just an on and off momentary switch, so just run a jumper wire between the 2 contacts, and if it runs, replace the switch , if it doesn't, use a meter to make sure the switch is actually getting power to it

your horn moght connected to the dynamo and not to the battery.
connect it to the battery .
dynamo is lacated at the wheel .

Yes! Please replace your power cable.
But try one first,if it works then you are certain you have to buy a new one.
Thanx

Alternator

The camera would have eventually turned off on it's own...it didn't stay on for 24 hours. Remove the card and battery...press all the buttons...leave it alone for 20 minutes...insert the card and then the battery...turn it on.