1988 procraft t.m. wiring ?

[came2fish]

i bought a 1988 procraft 1780 v comptitor. (used ) of course,, it has a 1991 motorguide t.m. that has a off-12/24 v. switch on the pedal. the boat schematic shows to wire the motor (for 2 batts.) with four cables, with one ground wire going to the switch for t.m. (on front panel) run/ off / charge ..? Motorguide however, say`s to wire with only three cables with a jumper from one batt. neg. post to the other batt. pos. post for 24v. operation ? does the swith on the panel from procraft eliminate the need to wire the batteries as motorguide suggests ??