It should be a rather simple matter to find your problem...
As TG mentioned...and, if the anser is NO to any of these steps, back up one step to resolve your problem...
1. do you have AC power to the new converter/charger?
2. with a digital volt-ohm meter, do you have POS & NEG
12 volt DC at the OUTPUT side of the converter - is the polarity correct?
3. do you have
12 volt DC at the input to the fuse panel?
4.have you checked the large amp fuses (or circuit breakers) that are in the fuse panel circuit to the battery cables?
5. check all fuses in the fuse panel for proper installation, blown fuses, etc...
In other words, start at the SOURCE and work your way through the wiring till you find where it isn't connected...