Electrical/Air Auxiliary System

Following the installation of the compressor (as described in the gallery here), below is the design, construction, and installation of the rear air and electrical system.
The goal is to install a control and operation panel that includes:

- Air outlet for tire inflation.
- Air pressure gauge for system control.
- Power switch for the water pump.
- Power switch for the rear light (mounted on the roof rack).
- Power switch for the compressor (bypassing the differential lock activation switch).
- Pair of 12V high-load outlets.
- 12V low-load outlet.

Materials

The base panel, as well as the control panel, were originally designed from aluminum, with the control panel intended to protrude and house the various switches. However, due to lack of knowledge in aluminum welding and other considerations (mainly shock resistance from the compressor and the vehicle), the material for the base panel was changed to marine birch plywood (thanks to Haim from Rehasim for the leftovers). Parts for the air system were purchased from Techno Tzinor in Tel Aviv.

Construction

The base panel was cut to match the shape of the original cardboard template, and two rectangles were cut from it. The goal was to leave a reinforcement strip in the center of the control panel. A step was cut around the perimeter of the rectangles using a Dremel tool to ensure that the control panel would sit recessed and at the same height level as the base panel. Holes were cut in the control panel to accommodate the switches, sockets, and the gauge. The control panel was sanded and glued to the base panel. The gaps were filled with wood glue mixed with sawdust and painted in a mahogany wood finish. Afterward, the entire panel was coated with clear spray lacquer. The edges of the panel, where the layers of the birch were exposed, were also painted in a mahogany wood color. The base panel was fitted with two L-shaped brackets that attached to the chair anchors (improvised from stainless steel brackets of a pot-hanging rod sold at Ikea). An additional birch panel was attached perpendicularly to provide vertical reinforcement, lying on the same surface used to anchor the compressor.

Power Installation

A 9mm² power cable was run from the battery, through a 60A maxi fuse to the area of the removed seventh seat. This cable is connected to an isolated power splitter from the company Autorewire, which includes a fuse for each output. This model of power splitter also comes with a minus splitter to which another 9mm² power cable was connected, running from it and connecting to the rear part of the frame. From the splitter, cables were run to the 7 consumers below:
- Water pump relay.
- Rear light relay.
- Compressor relay.
- Rear lock relay.
- Trio of 12V spark plug connections.

Air Pressure System

It is not recommended to operate differential locks directly from the compressor. A 0.3-liter fire extinguisher is used as an air reservoir. The fire extinguisher was cleaned, painted with hammerite, and a nozzle was installed allowing connection to the air pressure hose. To maintain the required air pressure, a pressure switch from the company Danfoss, model KP1, was installed. The switch will maintain air pressure of 85PSI with a 15PSI range. The switch is connected to the compressor relay and thus controls its operation.

Lock Operation

The plastic panel above the central mirror serves as a control panel for operating the locks. The panel was drilled, and 3 original ARB switches were installed. The middle switch operates the compressor, the left switch (near the driver) operates the rear lock, and the right switch (far from the driver) operates the front lock. The rear lock switch receives power from the compressor switch, and the front lock switch receives power from the rear lock switch. Disconnecting one of the switches disconnects those after it in the sequence. This ensures a proper operating order (compressor -> rear lock -> front lock) for both activation and deactivation of the locks. A three-wire cable was run from the panel to the rear part of the vehicle to operate the locks using relays.

Installation

A 1.5mm aluminum strip was bent and attached to the compressor bolts to serve as a base for the air splitter, which was secured using zip ties. The air splitter was equipped with a valve for system draining. An air hose was run from it to the vehicle. Another hose was run from the lock switch output to the outside so that any differential oil that might enter it would be expelled. The panel was installed, and the power cables, as well as the air hoses, were secured with zip ties. They were not tightly fastened to the vertical panel to allow movement during compressor operation. A 1.5mm reinforced aluminum panel was cut, its edges coated in plastic to prevent cuts, and installed in a way that seals the entire system assembly.

Overall, not a single new hole was drilled in the vehicle during the entire installation of the system, and existing screw holes were utilized.