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Autopapyrus · Range Rover Sport (2nd generation, L494) 3.0 TDV6
https://autopapyrus.com/guides/land-rover/range-rover-sport/eberspacher-hydronic-2-d5s-auxiliary-heater-wiring-and-installation-guide/
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) 3.0 TDV6: Eberspächer Hydronic 2 D5S Auxiliary Heater Wiring and Installation Guide

The Hydronic 2 D5S (about 5 kW) is a liquid-fired coolant heater that connects to the small coolant circuit and runs on diesel fuel from the tank. On the 3.0 TDV6 (diesel), fuel is drawn from the tank, and the coolant connects into the cabin heater circuit. The layout below is a general Hydronic 2 layout. The coolant and fuel branch points on the L494 depend on the specific trim and equipment, so connect strictly according to the markings on the connectors and harness of your kit.

Difficulty: Hard Time: 1-2 working days (installation with wiring) Steps: 11

Parts

11
№Part
01 Eberspächer Hydronic 2 D5S auxiliary heater (diesel, 12 V)
02 Fuel metering pump
03 Exhaust pipe with muffler
04 Combustion air intake pipe
05 Wiring harness
06 Fuse
07 Remote control or timer
08 Circulation pumpif not included with the heater
09 Coolant hoses
10 Coolant hose clamps
11 Fuel tap-in fitting

Tools

11
  • Socket and wrench set 8-19 mm
  • screwdrivers
  • multimeter
  • crimping tool and terminals
  • heat-shrink tubing
  • zip ties
  • wire cutters
  • drill with bits
  • hose pliers or hose removal tool
  • container for coolant
  • diagnostic adapter for checking heater operation
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

11 steps
  1. Preparation. Disconnect the negative battery terminal. Make sure the battery is in good condition: the heater draws a noticeable current during ignition (around 8-10 A at startup), and with a weak battery it will go into lockout due to low voltage. The heater control unit shuts off when the voltage drops below about 10 V.
  2. Placement. The heater is usually mounted in the engine bay near the front wheel arch, with the coolant pipes vertical or close to vertical so that air does not collect in the heat exchanger jacket. Route the exhaust pipe downward and out, away from the wheels and fuel lines. Place the combustion air intake in a spot free from splashes and dust.
  3. Coolant connection. Make the tie-in on the two heater hoses (supply and return) at the bulkhead. The heater inlet connects to the heater core return or to the engine outlet, and the heater outlet connects to the heater core supply. Install the circulation pump on the inlet or outlet pipe, following the flow arrow on the pump housing. Observe the flow direction according to the markings on the heater. After the tie-in, top up the coolant and bleed the air: warm up the engine with the cabin heater set to maximum, and top up again if necessary (twice).
  4. Fuel line. Mount the metering pump below the fuel level in the tank, on a bracket at the angle specified in the kit instructions (usually with the outlet fitting pointing up; the mounting angle is limited by the manufacturer's tolerance, about 15-35 degrees from horizontal). Draw fuel through the factory tee or a tap-in on the supply line (or a separate pickup tube in the tank). Fuel is delivered to the heater through a thin fuel line; do not route it near the exhaust. The line from the pump to the heater must rise without loops.
  5. Power supply. The main red power wire (positive) with a cross-section of at least 4 mm² runs from the positive battery terminal or from the power distribution block through a 20 A fuse installed close to the battery. The brown wire (ground) of the same gauge goes to the body or to the negative battery terminal. Crimp the connections with quality terminals and protect them with heat-shrink tubing.
  6. Heater control unit connectors. The harness has a main multi-pin connector, as well as separate two-pin connectors for the metering pump, the circulation pump, and the diagnostic circuit. Typical circuit assignments: power positive and ground, metering pump connection, output to the circulation pump (if it is controlled by the heater), output to the cabin blower relay (optional), switch-on input from the timer or button, and the diagnostic wire (W-Bus). Check the pin numbers and colors against the diagram supplied with the kit: colors differ between kit versions.
  7. Control. A timer or remote (with a display, GSM, or Bluetooth module) connects to the control unit. A wired timer is mounted in the cabin, and the harness is routed through a factory grommet in the bulkhead. The switch-on control wire can also be connected to a relay to turn on heat delivery when starting via a button, but do not connect it in parallel with the wires of the factory L494 modules and do not tap into the CAN wiring. Do not connect to the vehicle's CAN modules.
  8. Cabin blower. If you want the heater blower to run while the auxiliary heater is operating, do this only through a separate relay driven by the heater's control output, not through the factory L494 climate control module. Interfering with the factory climate control module and electronics is not required and is not recommended.
  9. Exhaust and air. Secure the pipes with clamps and avoid kinks. Point the outlet downward at a slope so that condensate drains outside. Keep the exhaust at least 10-15 cm away from plastic parts, wiring, and fuel lines, and install a heat shield if necessary.
  10. Checking and startup. Reconnect the negative battery terminal and check for fuel and coolant leaks. On the first start, fuel must fill the line, which takes several cycles. For the initial priming of the metering pump, use the fill mode in the heater diagnostics if available. Monitor the heating of the hoses first, then the warm-up of the coolant.
  11. Tightening torques. Tighten hose clamps moderately, without overtightening. Tighten the heater and bracket fasteners according to the kit instructions (usually in the range of 5-10 N·m (3.7-7.4 lb-ft) for M6 bolts). The exact value for your kit is in the product documentation.

Common mistakes and warnings

  • Working on the fuel system and wiring of a vehicle with the L494 electronic network requires experience
  • A mistake can lead to a fuel leak, fire, or module errors
  • Do not tap into the factory wiring without testing with a multimeter
  • If you lack experience, have the installation done by a specialist repair shop
  • Perform the first start-up outdoors, not in a closed garage: the heater exhaust contains carbon monoxide