It sounds like when the conversion was done originally, they put the wires on the back of the ammeter all on one terminal, thus bypassing it. When you hooked it back up (the way ot was f rom the factory) yes, it probably pegged it and it is now stuck. You may get lucky and a rap on the back of it with a screwdriver handle may un-stick it. Then you may want to put all the wires on one post and bypass it again.
