How to Install a Trailer Hitch on a 99 Grand Prix
- 1). Open the trunk lid. Lift up the trunk mat to reveal the spare tire and the tire changing tools. Remove the spare tire and the tire tools from the well in the bottom of the trunk compartment.
- 2). Pry up the rubber plugs from the sheet metal bottom of the spare tire well from inside the trunk compartment, using a flat-blade screwdriver. Place the plugs aside for future installation, or simply discard them.
- 3). Make a mental note of the hitch mounting bolt locations on the hitch so that they can be installed in the proper holes in subsequent steps. Remove the mounting bolts from the hitch, using a socket and ratchet wrench. Skip this step if the mounting hardware for your hitch is not already installed on the hitch.
- 4). Slide under the rear of the car and locate the two factory-drilled holes on the inside ledge of the metal inner rear bumper. Position the holes in the two small reinforcement plates that came with the hitch on the two factory-drilled holes on the ledge of the inner bumper.
- 5). Raise the hitch into position on the underside of the car. Line up the mounting holes in the hitch bumper hanger strap with the two factory-drilled holes in the rear inner bumper. Insert the mounting bolts that were removed from the hitch or came with the hitch mounting hardware kit through the holes in the straps and down through the reinforcement plates and the holes in the inner bumper. Place washers and nuts over the protruding ends of the bolts and tighten them finger-tight.
- 6). Apply a bead a silicone sealant around the underside of the mounting holes of the larger hitch reinforcement plate. Position the plate over the holes left open when the rubber plugs were removed from the upper side of the spare tire well. Insert the mounting bolts that were removed from the hitch or came with the hitch installation kit through the holes in the plate from inside the tire well, through the trunk floor and through the hitch front plate mounting holes. Place washers and nuts over the protruding ends of the bolts and tighten them finger-tight.
- 7). Tighten all hitch mounting bolts with a socket and torque wrench to the tightness specified by the hitch manufacturer. Replace the spare tire and tire tools. Close the trunk lid.
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