Express 3500 V8-6.6L DSL Turbo (2008)
Route the light green wire and brown wire inside the plastic floor harness retainer following the existing floor harness while securing with a tie strap (1).
Follow the floor harness until you get to the left front main harness pass-thru grommet. The light green wire and brown wire will be pushed through the
grommet and installed into the UBEC later.
Add circuit 47 (trailer brake signal) (dark blue wire).
Obtain a 12 (3.0 m) gauge dark blue wire and cut the wire to 122 cm (4 ft) in length.
Leave 61 cm (2 ft) of the dark blue wire inside the vehicle this end will be used to make up the trailer brake control module harness.
The opposite end of the dark blue wire will be pushed through the grommet and installed into the UBEC later in Step 47. Add circuit 3940 (battery feed)
(red/white wire).
Obtain a 12 (3.0 m) gauge red/white wire and cut the wire to 122 cm (4 ft) in length.
Leave 61 cm (2 ft) of the red/white wire inside the vehicle this end will be used to make up the trailer brake control module harness.
The opposite end of the red/white wire will be pushed through the grommet and installed into the UBEC later in Step 48. Add new circuit 6311
(CHMSL/stop lamp supply voltage signal) (light blue/white wire).
Obtain a 20 (0.5 m) gauge light blue/white wire and cut the wire to 152 cm (5 ft) in length.
Leave 61 cm (2 ft) of the light blue/white wire inside the vehicle this end will be used to make up the trailer brake control module harness.
The opposite end of the light blue/white wire will be pushed through the grommet and spliced into circuit 6311 later in Step 39.
