See also the pre-cut preparation discussion.
The Beetle’s rear wiring harness is routed over both fenders inside the luggage area, and extensions go through both sides of the hatch lid. In addition, some models have a CD changer and/or stereo Monsoon amplifier in the rear. All these wires need to be relocated to accommodate new Ute functionality and prepare the chassis for the truck bed installation.
In VW’s Puebla, Mexico plant, the Beetle’s harness was wrapped with adhesive tape which turns into a sticky goo that must be tediously unwrapped to separate wire extensions, leaving surfaces tacky and hard to handle.
Fortunately there is an inexpensive solution: split loom that comes in a variety of sizes to fit various wire bundles. After unwrapping, install new split loom over all the rear harness extensions to make the relocation job easier.
Previously the rear harness was protected from the weather inside the luggage area; the Ute transformation exposes the entire harness.
The harness could be routed up around the fender curve that would protect against sitting water on the chassis floor, but this would make wires completely inaccessible since they would be sandwiched between the fiberglass body and the aluminum bed wall.
To maintain accessibility, the harness must be routed along the chassis floor. To minimize moisture exposure, a simple way to keep the harness raised up just above the floor is to used zip tie cable mounts under plastic loom clips (keeps the loom about 0.3″ above the chassis floor).
The basic relocation plan is outlined below.
1 — left grommet: marker, park, turn, brake, reverse lights
2 — license light and camera pass-through (hole in existing plug)
3 — tailgate lock pigtail (new modification)
4 — right grommet: marker, park, turn, brake, reverse lights
5 — gas filler lid actuator routing change
6 — rear speakers* (connect outside the cabin)
7 — third brake light (connects inside the cabin)
8 — Monsoon amp and/or CD changer moved inside cabin
9 — truck bed light (connects via pass-through from inside cabin)
10 — relay for truck bed light switch warning indicator
11 — rear camera (connects to multimedia receiver)
Also: orphan leads and relocated chassis grounds
* if relevant, see 2-to-4 ohm speaker conversion issue below
The existing plug on the rear chassis frame can be re-purposed to pass the license plate wiring. Since the end connectors will be not reused, the cut wires can easily go through a small hole punched into the plastic plug.
A rear camera connection can also use this access. One new pass-through must be made to accommodate the relocation of the gas filler lid actuator pigtail on the right side.
Unlike the original wiring harness that stays inside the car, the Ute transformation requires a pass-through from the now-exposed rear into the cabin interior.
The pass-through locations are on the left and right near the seat belt assembly.
Rear speaker re-wiring
When replacing original 2 ohm Monsoon speakers with 4 ohm aftermarket products, the optimal solution may be to re-wire the rear speakers directly from a new stereo receiver to match power output. In this situation, these new wires will also use the side pass-through openings and the leads from the Monsoon amp would be eliminated.
The tabs on the Monsoon frame mount can be re-bent to conform to the cabin floor pan. The long Monsoon harness suggests that a passenger side location is the most practical.
Remove the rear carpet and underpad.
The two drainage holes in the floor pan, frequently damaged when the car is lifted incorrectly, should be sealed to prevent moisture from getting into the amp.
Filler lid actuator
The actuator for the gas filler lid, previously mounted inside on the top of the right fender arch, must be moved to a location where it still could be accessible for maintenance.
One alternative is to route the filler lid cable around the top of the fender and relocate the actuator to the outside of the fender arch. This would still allow access when the fender liner is removed. Wires can be passed through along the fender edge with a small grommet.
Harness ground connections
Various harness ground connections will need to be re-positioned. When fitting a new chassis ground, sand off all paint to insure good electrical connectivity.
A rear camera ground can be attached to the unassigned accessory outlet pigtail (brown wire); the 12v positive unswitched red lead remains unused (make sure to tape off the wire end to avoid an electrical short).
Since we have preserved the marker, backup, and third brake lights with their respective connectors, the only new pigtails we need to fabricate are for the rear turn/park/brake lights and license plate LEDs.
After the relocations are complete, test all the circuits for continuity and proper operation. Lights can be hooked up temporarily to make sure the wiring harness hasn’t been damaged. A VCDS scan also provides a helpful health check.
1. rear marker lights
2. rear turn signals
3. rear running lights
4. brake lights including third brake light
5. license plate lights
6. reverse (backup) lights
Reverse lights can be checked by turning on the ignition (without starting the engine), setting the handbrake, and then shifting into reverse gear. The backup lights should be illuminated.