Having ensured you understand the wiring diagrams and locations of various wires, the following are the steps that one would have to follow to check the wiper motor circuit, Making use of the 12 volt test light touch each terminal in turn that is at a connector to check voltage. If wipers run slow, check battery condition and charge if needed; if wiper motor is suspect replace the motor and while wiper motor is out manually operate the wiper arms and check for binding in the linkage and pivots and lubricate or repair as needed before reinstalling the motor. If wipers still operate slowly, check for loose or corroded connections, especially the ground and if connections tested good, replace the motor. If wipers are not working, check the fuse in the driver side interior fuse box, if it is good, connect a jumper wire between the wiper motor ground terminal and ground and then turn on the wipers. If the motor is running, fix the ground; if the motor is not running, check for the voltage at the motor with the wiper switch on high. To work on the electrical connector, the cowl louver panels needs to be removed. If there is voltage at the connector, remove the motor and apply tests off the car using fused jumper wires connected to a battery. If it works, look for binding linkage; if it does not, replace the motor. If there is no voltage to the motor, go and check the voltage at the wiper control relays; if voltage is present at the relay but not at the motor, it is advised to test the switch; if the switch turns out to be good, then the wiper control relay may be a problem. For inoperative interval function, refer to the continuity of wires between the switch and wiper control module. If wipers do not park when the switch is turned off, look for voltage at the park feed wire of the wiper motor connector with the switch off and ignition on; if there is no voltage, look for a break in the circuit between the wiper motor and the fuse panel. For replacement, remove the negative battery terminal, remove covers over the wiper arm mounting nuts, and then remove the nuts while noting the relative position between the wiper arms and the spindles before lifting up the wiper arms. First, remove the cowl louver panels, then unplug the wiper motor harness connector, and finally, unscrew the windshield wiper motor/linkage assembly. Move the assembly towards the passenger side to pull the rubber pin near the motor from the cowl sheet metal then pull the assembly out. Take off the linkage from the motor arm, unbolt the wiper motor and detach the motor from the frame with the procedure for assembly being the reverse of disassembly. For the liftgate rear wiper, unbolt the wiper arm and wiper arm cover and then open the liftgate and pull off the rear wiper assembly trim panel using a trim tool. Detach and unscrew the electrical junction of the wiper assembly, then remove the mounting bolts and assemble together with the wiper assembly, and then reverse the process.
Posted by GMPartsGiant Specialist 
