Plumbing in Hot and Cold Air to the Rear Seats of a Defender

Available for Manual Transmission Defenders Models pre 2007

One of the biggest headaches when trying to cool the interior of a Defender is poor circulation of air into the rear cabin area, especially so in the longer wheelbase 110 and 130 models. Fitting our secondary HVAC unit to directly service the rear passengers is something that makes a massive difference to the overall cabin environment. Sitting neatly between the front seats of your Defender, this powerful unit incorporates its own Evaporator and Heater cores. Linked to a powerful 3 speed blower, our second row HVAC is not simply a way to transfer cold air from the front into the rear, but is an actual secondary AC, working specifically for the rear seat passengers.

Rear HVAC Plumbing

Connect the #6 T section into the Front AC system, between the drier bottle and the HVAC unit. This will be the refrigerant supply line to the rear AC unit.

Connect the #10 T section into the Front AC system, between the HVAC unit and the Compressor. This will be the refrigerant return line from the rear AC unit.

Connect the Flow Solenoid to the Rear HVAC #6 supply line, IMPORTANT: The Solenoid is directional, please note the direction arrow on the valve case.

Connect the Rear Heater using the T-Piece provided onto the inlet water pipe between the flow valve and the HVAC unit. This will be the hot water supply line.

Connect the Rear Heater using the T-Piece provided onto the water return pipe between the HVAC unit and the bleed valve. This will be the water return line.

Note: Remove all air from the heating system prior to use.

Rear AC Wiring Installation

Electrical installation depends on whether the rear unit is to be added to a Defender that already has an existing front AC system, or whether this rear unit is to be fitted as part of a complete new install of both front and rear HVAC systems supplied by Ministry of Defender.

Simple Wiring when Adding Rear AC to an Already Fitted Front HVAC System:

• Blue 20a Wire: Ignition feed for Blower
• Orange 10a Wire: Trigger line to #6 Solenoid Connects directly to #6 Solenoid + Wire
• Grey 10a Wire: Backlight Feed from Dashboard Sidelights to illuminate the AC Switch
• Black 20a Wire: Ground/Earth

Combined Front and Rear HVAC Install

If installing both front and rear MoD units at the same time, a complete Plug-and-Play wiring harness will be supplied along with a relay box/control module. The control module is designed to sit in the Defender battery box and can be wired directly to the battery terminals. All other plugs on the MoD loom are labelled for ease of fitting. It is recommended that you familiarise yourself with the wiring loom by laying it out on the floor first. This will give you a proper understanding of where each component fits on the electrical circuit and can aid installation and loom routing.

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