- Dirt Road Magazine - Under-Body Lighting

- Dirt Road Magazine - Under-Body Lighting - (dirtroad.com)

Š2008 Dirt Road Magazine

Would you be surprised to learn that the under-body lighting shown on our TJ in this picture cost us less than $20 to install? It's true!
In this article, we are going to take you, step-by-step, through the installation of the same under-body lighting we are using on our 1997 Wrangler Project, Stubby. We have used these lights for years, and have never broken a single one, not even in Moab.
These lights are readily found in local stores, and use a standard inexpensive bulb. They are designed for area illumination only (to light the area on the ground directly beneath the installation area), and are not meant to be used as driving lights.
As shown on our TJ, they can be installed just about anywhere you like. Our front-mounted light illuminates the entire front axle assembly making trail-fixes much easier.
Though these lights can be wired directly to a switch, we hooked ours up so they turn on with the interior lights (i.e. when the doors are opened). Our two primary lights shine onto the ground at the foot of each door, another lights up the front area of the Jeep, and two more are now mounted in the rear.
I'd like to point out that I did not install these lights to "look cool". I came up with the idea because I was tired of getting out of my vehicle in the dark and stepping into a puddle, off a ledge, onto a snake, etc. They are also very helpful for seeing the area around the Jeep when wheeling or performing repairs at night.

The tools we'll need:
Power drill

Nut-rivet set (try Harbor Freight)
Steel nut-rivets
Screw driver
14-16G Electrical Wire

The lights we'll use are available from most local hardware stores, and some discount stores.
Shown at left are two different brands of the same basic light:
Blazer #C669BU
PM (Peterson Mfg) #V392C
Both lights are labeled "Back-Up Light", and sell for about $5.95 each. They are generally found near the trailer lights & supplies section.

Step 1: Select a Mounting Location
Find a location on the frame that already has a large enough hole for the light's bulb socket.
(Since we already have lights mounted under our doors, we installed more lights at the rear for this article).

Step 2: Mark and Drill
Disassemble the light components and separate the base from the rest of the parts.
(Though the package directions say to drill at the four inside holes of the light base, we usually drill holes at the outside ring instead (as shown), for better stability, and more working room. Either way is fine.)
Place the base on the frame in the selected location. Rotate the base to make sure both mounting holes are on the frame (see picture).
Mark your drilling locations and drill a small pilot hole. Replace the light base and recheck hole placement. Then, re-drill with correct-size drill bit.

Step 3: Insert a steel nut-rivet and crimp into place. (Aluminum nut-rivets are generally too soft.)
We used #10-24.

Step 4: Run Wiring to Light
Thread the electrical wire through the frame from the passenger compartment to the location selected for the light. Only one wire is needed per light - each light grounds directly to the frame.
(This picture shows how we ran the wire up through the floorboard of our TJ through a drain-plug.)

Step 5: Assemble the Light
Use Loctite on the machine screws that secure the light to the frame. (We used stainless-steel hardware.)

Step 6: Complete the Wiring
There are three primary ways to set-up the wiring for these lights, so they

turn on when your dome light is on,
turn on when the doors are open (a second door-pin switch will need to be installed, see picture. We used a Painless wiring pin switch - see white arrow in top photo), or
turn on when a dedicated switch is closed.
Be sure to wire the new lights through a relay (see relay marked by the white arrow in second photo).
Also, be sure to fuse the circuit (see the blue arrow in second photo).
Relay contact wiring:

#87 to the new lights.
#30 to constant 12V+
#85 to ground
#86 can attach to the dome light circuit at the fuseblock (lights come on with dome light), or to a 12v+ powered switch for manual control.

Click here for more information about using relays.

The Completed Project

Dirt Road Magazine is sponsored by Turner 4WD Parts Co.