← Range Rover Sport Land Rover Range Rover Sport repair manuals →
Autopapyrus · Range Rover Sport (2nd generation, L494)
https://autopapyrus.com/guides/land-rover/range-rover-sport/wiring-diagram-for-the-eberspacher-hydronic-ii-d5s-fuel-fired-heater/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Range Rover Sport (2nd generation, L494): Wiring Diagram for the Eberspächer Hydronic II D5S Fuel-Fired Heater

The D5S connects through four circuits: main power, fuel metering pump, control, and signal circuits (diagnostics, circulation pump). For this vehicle, the general rule is to take power directly from the battery and route the control signal to a separate module or timer. Do not tap into the vehicle's CAN bus. Check the exact wire colors and pinout against the label on your kit's harness, because they depend on the heater series.

Difficulty: Hard Time: 4-8 hours (installation and wiring) Steps: 7

Parts

5
№Part
01 Eberspächer Hydronic II D5S fuel-fired heater kit, diesel, 12 V
02 20-25 A fuse in holder
03 Copper wire, 4 mm²
04 Copper wire, 1.5-2.5 mm²
05 Solderless terminals and butt connectors

Tools

9
  • multimeter
  • set of 8-13 mm wrenches and sockets
  • terminal crimping tool
  • heat-shrink butt connectors
  • fabric harness tape
  • zip ties
  • side cutters
  • metal drill bit
  • Torx wrench
There's a full repair manual for this car Every system, wiring diagrams and torque specs — not just this job. Haynes AutoFix (online) and 1 more. See manuals →

Step by step

7 steps
  1. Main power. The positive lead runs from the battery terminal or a power distribution point in the engine bay through a 20-25 A fuse, which must be installed no more than 30 cm from the positive terminal. The negative lead goes to the body ground: clean the contact point down to bare metal and treat it against corrosion. The wire gauge is specified in the kit, usually 4 mm² for powering the unit. On the L494, the battery is managed by an intelligent charging system, so do not connect the negative to the battery terminal itself or to its sensor. Use the nearest body ground point or the main negative stud.
  2. Heater control unit. It is powered from the main harness and has a connector with signal circuits: a control input from the timer, a circulation pump output, and a diagnostic input. These wires run into the cabin to the timer or remote start module. Do not mix them up with the power wires. Check each wire with a multimeter against the diagram in the kit.
  3. Fuel metering pump. This is a separate connector with two wires (positive and ground, both controlled by the heater unit). It plugs into the heater harness, so do not supply it with power directly from the battery. Mount the pump under the floor, at an angle of about 15-35° as specified in the kit, and well away from the exhaust.
  4. Circulation pump. If the kit includes a separate pump, connect it to the heater control unit output (positive switched by the unit's signal, ground to the body). Plumb the pump into the engine coolant circuit as shown in the kit diagram.
  5. Timer or switching module. Power the module from a factory constant-positive circuit through a separate 5-10 A fuse, and run the control signal to the heater unit as shown in the kit diagram. Do not touch or tap into the factory harnesses, the CAN bus, or the vehicle's control modules. L494 modules are sensitive to voltage drops and electrical interference from added equipment.
  6. Wire routing and protection. Route the harness away from the exhaust, sharp edges, and moving parts. Cover all connections with heat-shrink tubing and secure the wires with zip ties. Use grommets wherever wires pass through panels.
  7. Testing. Reconnect the battery and measure the voltage at the main power connector (about 12 V with the engine off). Start the heater from the timer: it should run a purge cycle, deliver fuel, and reach operating mode. Check that no errors appear on the instrument cluster. If the heater sets a fault code, read it from the blinking indicator or with Eberspächer diagnostic equipment.

Common mistakes and warnings

  • The heater's fuel and exhaust components are fire hazards
  • Incorrect exhaust routing can cause a fire or carbon monoxide poisoning
  • Never run the heater in a closed garage
  • Disconnect the negative battery terminal before starting work, and be aware that on this vehicle, disconnecting the battery may require resetting the electronic systems and recalibrating the windows and suspension
  • If you have no experience with electrical and fuel systems, have a repair shop do the installation, and note that your vehicle warranty may depend on how the heater is wired