2017~2024 How to get accessory wiring through firewall

To get vehicle accessory wiring (such as trailer wiring power) through the firewall, locate the vehicle wiring harness slightly above and to the left of the brake and acceleration pedals. Remove the fuse box cover and the the plastic molded panel that surrounds the fuse box. The vehicle wiring passes through the firewall via a 3-4 inch diameter rubber grommet. There are two holes through the grommet from the interior of the vehicle. Next, locate the battery under the hood in the engine bay directly ahead of the driver position. Remove the red and black wires and then remove the battery. This is done for ease of access to the grommet from the engine bay in order to obtain the wire. Look for two small rubber protrusions (nipples) on the grommet, these should line ip with the holes in the grommet in the cab. Use a flashlight and you will be able to see from the cab. Using a small screwdriver or metal pick or wire clothes hanger (or the like), insert through the hole, push and poke through the nipple. Then simply push the wire through and grasp it from the other side. Complete the wiring, replace the battery and interior panels.
 
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