if you locate the motor i e mine is behind the molding on the slide out at the top.. use a multimeter at the last two wires to touch the motor.. unplug them and put the probes in each wire get good connection_ set the meter and have someone turn the switch to the slider_ if your reading is 12 v or more than all is good from that point_ if not then work backwards _ if reading is 12 v or 14 v then yes motor could be bad,,, check for binding also .. good luck .. kennyg