My invacare pronto m51 wheelchair does not turn on. we just had the battery replaced. when it is plugged in the battery lights turn on and when you unplug it they do not even turn on.

Did you replace both batteries? How old is the chair? Sometimes the on-off keypad becomes worn and does not make contact with the on-off switch. When charging the joystick lights can light up but after unplugging they should remain on. When you plug in the charger look under the rear cover at the charger you should see 2 lights, one red and one yellow to indicate that you are charging the chair if you do not see both lights lit then the charger is bad or has a blown fuse. Only a Tech will be able to tell what is wrong. If Medicare purchased your chair then they will pay for most of repair costs. Contact your provider or a repair service company