Hole Size on Reese Underbed 5th Wheel Install Kit Pucks and 5th Wheel Trailer Wiring 2010 Ford F-250

Updated 09/05/2012 | Published 08/31/2012

Question:

I have a 2010 F250 Super duty short bed and am installing the hitch assy myself and was curious as to the hole size needed in the bed for the pucks? I think i read some where 3 1/2inch but also remember seeing 3inch i think? I have a Signature series 18k 5th wheel hitch on slides for this vehicle and ordered this assy for it. I am also curious about the proper or best wiring harness for this aplication and or vehicle to avoid splicing into wires. also is there a specific location for mounting the harness that is best? front of wheel well or behind?

asked by: Mike C

Expert Reply:

When installing the underbed 5th wheel installation kit # RP30073 the holes for the pucks need to be 2-1/2 inches as indicated in the instructions that I have linked for you. You will need a 2-1/2 inch hole saw to make the cuts.

If your 2010 Ford F-250 came with a factory 7-Way trailer connector at the back, you can use gooseneck/fifth wheel wiring harness # 50-97-410, and it will just plug in line with the factory wiring. The wiring harness is 9 feet long so you can install it ahead or behind the wheel well depending on what is best for you and your trailer. I have linked a video showing a typical installation. It is on a different make truck but installation is the same on a Ford.

If the truck came with a 4-Way but not a 7-Way you will need to add a 7-Way using # 37185 and then use # 20027.

expert reply by: Michael H