wiper motor

1989 ford ranger,my passenger side wiper arm stop on a sunday night,drivers side ok and would not be able to get to it till following weekend.Driver side worked till friday, when leaving work, drivers arm started twice it parked in the up position.I accessed the panel on the firewall, turned on wipers and of course no movement on linkage, but slight twitching of the motor. Before I replace the motor could it be anythig else. thanks