The Pontiac Grand Prix’s history dates back to its original release as a two-door muscle car in 1962. Throughout its lifespan, the Grand Prix slowly morphed into a compact, family-oriented type of vehicle. The 1998 Grand Prix came standard as the four-door SE trim level, which included power windows. Each of the Grand Prix’s four doors has a power window regulator and motor that work together to raise or lower the window. Replacing the power window regulator and motor on the 1998 Grand Prix requires removing the door panel, but it is a straightforward task from there.
Insert a flat-head screwdriver’s blade under the front of the power accessory switch bezel – the bezel that houses the power window and door lock switch – and pry upward to release the retaining clip. Repeat this step on the rear of the switch bezel, then lift the switch high enough to access the wiring harness. Unplug the wiring harnesses and remove the switch bezel with the switch attached.
Pry the screw covers from under the pull handle, exposing the trim panel screws. Remove these screws with a ratchet and socket.
Unfasten the trim panel’s retaining clips by prying around the perimeter of the panel with a trim stick. Pull the door panel outward, carefully guiding the inside door handle through its cutout in the panel, just enough to access the remaining wiring harnesses connected to door panel-mounted electronics and unplug the harnesses. Remove the door panel.
Peel the water shield away from the door, using extreme care so you do not rip it. When you get to the inside door handle, carefully guide the cutout in the shield around the handle. Set the water shield in a clean environment with its adhesive side facing up.
Grip the base of the window with both hands and lift it to its full-up position, if needed. Using three or four 12-inch-long strips of high-quality duct tape, tape the window in the full-up position. If the window will not lift, you can clip the motor-to-regulator cables, using cutting pliers, but have an assistant hold the window in place as you cut the cables.
Reach into the door and unplug the window motor wiring harness. Remove the two window-to-regulator bolts with a ratchet and socket. Remove the four regulator-to-door bolts, then the three window motor-to-door bolts.
Pull the regulator and motor out through the large access hole in the door.
Guide the new regulator-and-motor assembly into the door through the large access hole. Align the regulator-to-door mounting holes with those in the door. Hand-thread the regulator-to-door mounting bolts then torque them to 89 inch-pounds, using an inch-pound torque wrench and socket, in the following sequence: bottom rear, top rear, bottom front, then top front.
Line up the motor’s mounting holes with those in the door and hand-tighten the motor-to-door bolts. Torque the motor-to-door bolts to 89 inch-pounds. Connect the wiring harness to the window motor.
Instruct an assistant to hold the window in place, as you remove the duct tape from the window. Tell your assistant to lower the window slowly and evenly until the bolt holes on the lower window guides align with the bolt holes in the regulator’s lift plate. Hand-tighten the window-to-regulator bolts, then snug them with a ratchet and socket.
Align the door’s water shield with its raised mounting ridge on the door and guide the inside door handle through the cutout in the shield. Lightly press around the perimeter of the shield to set the water shield into place. Using a kitchen rolling pin or an automotive upholstery roller, roll along the perimeter of the water shield to seat it firmly in place.
Reconnect the wiring harnesses to their respective door panel-mounted electrical components. Line up the retaining clips on the rear of the door panel with the holes in the door. Press the panel onto the door until the clips snap into place.
Tighten the door panel screws to 18 inch-pounds, using an inch-pound torque wrench and socket. Press the screw covers into place over the screws.
Plug the wiring harnesses into their respective switches on the power accessory bezel, then align the retaining clips on the bezel with the slots in the door panel. Press the bezel downward to lock it into place.
Unfasten and remove the power accessory bezel by following Step 1 in the section titled “Front Removal.”
Remove the screw covers inside the door handle pull cup by prying them upward with a flat-head screwdriver. Remove the screws inside the pull cup, using a ratchet and socket.
Pry around the outside edge of the door panel with a trim stick to disengage the door panel-retaining clips. Pull the door panel from the door.
Follow steps 4 through 7 in the section titled “Front Removal” to remove the rear door motor and regulator.
Install the regulator and motor by following steps 1 through 4 in the section titled “Front Installation.”
Line up the retaining clips on the rear of the door panel with the holes in the door. Press the panel onto the door until you hear the clips snap into place. Tighten the door panel screws to 18 inch-pounds, then press the screw covers into place in the pull cup.
Plug the wiring harness into the power window switch. Line up the clips on the power accessory switch bezel with the slots in the door panel, then press the bezel downward to snap it into
