windshield wipers

replace wiper motor pulse board. its under the black cover on w/motor. When you install cover apply a 1/8" wide bead of form-a-gasket to cover in path where it contacts motor. this was very common problem for a block of years of gm trucks. condensation would form and/or moisture would get in and mess with the pulse board my experience has been 1/2 of them end up damaging the multifunction switch which costs several hundred still

sounds like a motor or control issue. probably the motor. straight forward repair Roy