GM Service Manual Online
For 1990-2009 cars only

Object Number: 296621  Size: SH

Option UY7 is an 8 wire trailer harness. It can be ordered as part of the Trailering Package. The UY7 harness consists in part of an orange (ORN) 30 amp battery feed wire and a dark blue (DK BLU) wire. The dark blue wire is available for an auxiliary circuit, such as electric trailer brakes. The orange wire originates at the convenience center. The orange wire is protected by an in-line fuse. The dark blue (DK BLU) wire is taped to the battery feed wire near the bulkhead connector. This portion of the harness routes through the left wheelhouse conduit, across the left sill, up the B-pillar to the rear of the vehicle. The harness continues across the top of the rear door(s) and down the right D-pillar. The harness is secured with a strap and looped behind the right wheelhouse.

The rest of the trailer harness is spliced from the rear lamp harness, which contains the wiring for the brake/parking lamps, the turn signals, the backup lamps, and the ground. The UY7 option does not include a connector at the end of the harness. A connector must be wired to the harness after production by a trained service technician.

The UY7 harness contains the following 8 wires:

    • The orange wire: The 30 amp fuse battery feed
    • The light green wire: The backup lamps
    • The dark blue wire: An auxiliary circuit
    • The brown wire: The taillamps and the license lamps
    • The dark green wire: The right turn signal and the stoplamp
    • The yellow wire: The left turn signal and the stoplamp
    • The white wire: The ground wire
    • The white wire: The trailer center high mounted stoplamp (CHMSL) feed

Once the harness is attached, observe the following precautions when using the harness:

  1. Carefully route the harness between the door and the floor sill.
  2. Do not pinch or cut the wiring.
  3. Leave enough of the harness on both sides of the door to prevent the harness from being pulled by either the trailer or the body.
  4. Do not allow the harness to drag on the ground.
  5. When the harness is in use, tape or strap the trailer portion of the harness to the tongue of the trailer.
  6. This will prevent the harness from dragging on the ground.

  7. When the harness is not in use, wrap the harness together and bind the harness with a tie strap in order to prevent damage.
  8. Store the harness behind the rear wheel housing on the passenger side of the vehicle