When checking wiper functionality, note that power wires are typically larger and brighter, while ground wires are smaller and darker. To verify voltage, use a grounded 12-volt test light on each terminal at a connector until it lights. If wipers operate slowly, ensure the battery is in good condition and fully charged; if so, remove the wiper motor and manually operate the wiper arms, checking for binding in the linkage and pivots, which should be lubricated or repaired as needed before reinstalling the motor. If wipers still operate slowly, inspect for loose or corroded connections, particularly the ground. For wipers that fail to activate, check the 
Fuse; if intact, connect a jumper wire between the wiper motor and ground, then retest. If the motor operates, repair the ground connection; if not, check for voltage at the motor and test it off the vehicle with jumper wires. If the motor works, inspect for binding linkage; if it doesn't, replace the motor. If there's no voltage at the motor, check the switch for voltage and the wiring for continuity. For wipers that only work on one speed, check the continuity of the wires and terminals; if they are fine, replace the switch. If the interval function is inoperative, check the wiring continuity and replace the interval module if necessary. For wipers that fail to park, check for voltage at the motor with the switch off and ignition on; if voltage is present, the limit switch is faulty, requiring motor replacement. If wipers won't shut off unless the ignition is off, disconnect the wiring from the control switch; if they stop, replace the switch, but if they continue, the limit switch in the motor is defective and needs replacement. For wipers that won't retract below the hoodline, check for mechanical obstructions and inspect the wiring for continuity; if the wiring is fine, replace the motor. To replace the wiper motor, remove the wiper arms and cowl covers, then take out the wiper linkage retaining bolts along with the motor. For the rear wiper motor, remove the liftgate interior trim panel and the wiper arm before taking out the motor and linkage mounting bolts. Finally, remove the bolts to detach the motor from the linkage assembly, and installation follows the reverse order of removal.