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Eberspächer Airtronic D4 wiring diagram
Original 12 V Airtronic D4 diesel air heater: 900–4000 W thermal output, 7–40 W electrical running consumption and up to 100 W during starting. Preserve its 20 A main fuse, separate control protection and controller-driven shutdown cycle.
- Compatible systems
- 12 V
- Rated power
- 40 W
- Continuous draw
- 4 A
Wiring diagram
How the Airtronic D4 is wired.
Open this example in Crimp to use your own parts and cable lengths. Review the assumptions and installation notes as you adapt the circuit.
Cable sizing for this example
Use the diagram as a starting point for your installation. Replace the example equipment and cable lengths with your own, and check the connections against your exact model's instructions.
3 m one way
12 V system
- Wire
- 1.5 mm² · 16 AWG
- Example fuse
- 7.5 A
- Design current
- 4 A
- Voltage drop
- 2.4%
Sized against ABYC E-11. The design current is the part's continuous draw. The length is one way; voltage drop includes an equal-length return.
Run-length and manufacturer assumptions
The editable example uses 3.048 m (10 ft) runs unless a shorter run is stated. Metric overviews round these to 3 m. Adapt the parts and lengths to your installation before choosing cable and protection.
Supporting parts
- 6.1 m total of 1.5 mm² (16 AWG) marine cable
- Terminations for 1.5 mm² cable, matched to the equipment's screw terminals, leads or studs
- 7.5 A fuse and holder on the positive run
- Heat-shrink, strain relief and terminal boots sized to the cable
Check stud sizes, fuse type, run length and how warm the space gets against the gear you actually have before you order.
Installation notes
Before you install.
Open a question for model-specific guidance and sources.
Verified against the manufacturer's documentation (rev. 20339 Issue F \u2014 December 2011), checked 2026-10-01. Manufacturer documentation →
Original D4 generation
This note covers the original Airtronic D4 in the D2/D4/D4+ manual. It does not substitute the specifications of D4 Plus, Airtronic M2 or later S3/M3 heaters. The D4 has four heating stages up to 4000 W thermal output. Electrical draw is 7/13/24/40 W across the stages, with starting consumption up to 100 W; thermal output is not battery consumption.
Supply and control protection
The diagram’s `+` and `−` are the heater power feed and return. The manufacturer circuit diagram specifies a 20 A main fuse for the 12 V version, 10 A for the 24 V version, and a separate 5 A switch fuse. The controller, fuel dosing pump and sensor connections are separate from this supply. Select cable size for the complete run and starting voltage drop; a small average draw does not justify an undersized feed.
Shutdown and voltage limits
Switch off through the heater controller and allow its after-run sequence to finish. Cutting the main feed as a normal thermostat or on/off method prevents the intended cooling and cleaning cycle. The original 12 V controller shuts down after approximately 20 seconds below 10.5 V or above 16 V. If starts fail, measure voltage at the heater during glow operation and inspect the feed and return connections.
Installation beyond the drawing
The model omits exhaust, combustion-air and fuel installation, dosing-pump wiring, room-temperature sensing and the controller. A correctly fused two-wire supply does not establish a safe heater installation. Use the manufacturer marine-installation guidance for the fitted kit and retain separation of exhaust and air paths. Confirm the data-plate voltage before using a 24 V family diagram; this catalog item represents the 12 V configuration.
Source: manufacturer document — technical table p. 4; operating sequence pp. 17–18; short-loom circuit p. 21; safety pp. 30–31 (printed/PDF).
Fit check
Connect it to the rest of your system.
Describe your setup to draft a system with Airtronic D4 connected. Review the selected parts and cable lengths, then edit the diagram in Crimp.
The model only picks parts and draws the connections. Every wire size and fuse rating still comes from Crimp's own sizing, never from the model.
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Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
Original 12 V Airtronic D4 diesel air heater: 900–4000 W thermal output, 7–40 W electrical running consumption and up to 100 W during starting. Preserve its 20 A main fuse, separate control protection and controller-driven shutdown cycle.
- Compatible systems
- 12 V
- Rated power
- 40 W
- Continuous draw
- 4 A
- Surge current
- 10 A
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
+
positive · input
−
negative · input
Sources and sizing method
Equipment specifications. Model details, ratings and terminal roles come from the catalog. Check your unit’s label and current manufacturer documentation for its exact revision.
Example sizing. Sized against ABYC E-11. Boats built to UK or EU rules answer to ISO 13297 — check these figures against it before you build. Results use the example current and run length shown above. Set your actual equipment, lengths and installation conditions in Crimp before choosing hardware.
Read how the sizing worksNext step
Plan your installation with Airtronic D4.
Open this example as a new project, or add this component to your existing diagram. Use your equipment and cable lengths to review the sizing.
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