ONAIR / Installation & Setups
Compressor wiring, without the guesswork.
Understand what the fuse, relay and power wiring do before planning the electrical side of an air-ride install.
Use the wiring diagrams and ratings for the exact compressor and management system. Cable size, fuse selection, relay capacity and grounding depend on the equipment, circuit length and installation. There is no single wire-gauge or relay-pin recipe for every build.
The fuse and cable must be selected as part of the same circuit.
The relay handles the intended load; the control signal is a different job.
Adding a compressor requires an electrical plan, not a splice by assumption.
01 / THE DETAILS
Separate the control signal from motor power.
The controller or pressure-control arrangement decides when filling is needed. The correctly rated switching circuit supplies the compressor. Do not route compressor motor current through a small control output unless the manufacturer explicitly designed it for that load.
| Part | Job |
|---|---|
| Power cable | Carries the required current over the installed circuit length. |
| Circuit protection | Protects the circuit according to the wire and equipment requirements. |
| Relay or specified power switch | Switches the compressor load using the correct control arrangement. |
| Ground/return | Completes the circuit with an appropriate, secure low-resistance connection. |
02 / THE DETAILS
Gather the diagrams before choosing wire.
- Compressor supply voltage, current draw and duty limits.
- Required circuit protection and the manufacturer's placement instructions.
- Relay rating, terminal diagram and any polarity-sensitive components.
- Management trigger, ignition and pressure-control wiring.
- Actual cable route and total circuit length.
ONAIR 2V currently uses pressure control built into its manifold. The current 4V listing uses an external tank pressure switch. That difference is one reason to avoid copying a diagram from another controller.
03 / THE DETAILS
Size for the installed circuit.
Current, run length, acceptable voltage drop, temperature and routing conditions influence cable selection. Use suitable automotive cable and terminations. A fuse must not be oversized simply because the previous one kept opening.
For two compressors, confirm the combined vehicle electrical demand and the required individual circuits and protection. A single-compressor harness is not automatically suitable for a second motor.
04 / THE DETAILS
Good routing is part of the design.
Protect wiring from sharp edges, moving suspension parts and heat. Use proper pass-through protection, secure the loom and leave service access. Follow the specified grounding arrangement instead of choosing a convenient-looking painted panel.
Have the work checked before energising. Isolate power using the approved procedure before service, and disable automatic suspension functions as instructed.
05 / THE DETAILS
Stop when the circuit is telling you something.
Do not bypass a fuse, bridge a relay or wrap damaged power wiring and continue driving. Have the wiring and load checked by a qualified installer.
Save the finished wiring diagram and fuse locations with the car. Good documentation makes a future fault much easier to trace.
ONE MORE THING
The questions that come next.
What wire gauge should I use?
Use the compressor manufacturer's requirements together with the actual circuit length and installation conditions. A gauge quoted for another car may be unsuitable.
Are relay pin numbers always interchangeable?
No. Read the diagram on the actual relay and the supplied harness instructions, including polarity-sensitive suppression where fitted.
Can the pressure switch power both compressors directly?
Only use the arrangement explicitly rated and specified for the system. Do not assume a control switch can carry two compressor motor loads.
Sources & equipment references
General education is not a replacement for the instructions supplied with your exact components. Product-specific ratings and procedures do not transfer automatically to another setup.
- ONAIR 2V compressor control and wiring
Current integrated pressure-control arrangement; the supplied diagram takes priority.
- ONAIR 4V compressor control and wiring
Current external pressure-switch and relay arrangement.
- VIAIR installation FAQ
Electrical load and multiple-compressor considerations; model-specific instructions remain necessary.
