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Parts Guide
Ignition-Switched Anderson Plug Kits: The Caravan Wiring Upgrade That Actually Matters
Your Anderson plug isn't doing its job — unless it's ignition-switched.
Ignition-Switched Anderson Plug Kits – The Essential Upgrade Many Caravan Owners Forget
When setting up a new tow vehicle, most people immediately think about fitting
an electric brake controller, bull bar, driving lights or a UHF radio.
But one of the most important towing upgrades is often overlooked… An Ignition-Switched Anderson Plug
When most people set up a new tow vehicle, the checklist looks something like this: brake controller, bull bar, driving lights, maybe a UHF radio.
An Anderson plug barely gets a mention — and when it does, it’s often just whatever the auto sparky had lying around.
That’s a problem. Because if your Anderson plug isn’t ignition-switched, there’s a decent chance your caravan’s battery isn’t charging the way you think it is — and your next trip could end with flat batteries and a fridge full of warm beer somewhere west of Broken Hill.
Here’s what you actually need to know.
The Basics
What Does "Ignition-Switched" Actually Mean?
A standard Anderson plug connection runs directly from your vehicle’s battery. It’s always live. That means power is flowing whether the engine is running or not.
An ignition-switched (or ignition-isolated) setup is different. A relay in the circuit monitors the ignition. When you start the engine, the relay closes and power flows to the caravan. When you turn the key off, the relay opens and the circuit is broken.
The result: your caravan’s charging system only activates when your engine is running. There’s no risk of the caravan accessories quietly draining your start battery overnight.
⚠️ Modern Vehicles Don't Work With a Standard VSR
Older vehicles with simple alternators could get away with a permanent Anderson connection and a voltage-sensitive relay (VSR). The VSR would open when battery voltage rose above a set point, indicating the alternator was running.
Modern 4WDs don't work like that. Smart alternators — common in vehicles like the LandCruiser 300 Series, Hilux, Ranger, and most modern dual-cab utes — actively vary their charge voltage to save fuel. Voltage can drop well below the VSR threshold even with the engine running. A VSR-based system reads this as "engine off" and disconnects the caravan charging circuit entirely.
An ignition-switched system doesn't care about voltage. It reads the ignition signal directly — so the relay stays closed whenever the engine is running, regardless of what the alternator is doing. If you're towing with a modern vehicle, ignition-switched is the only reliable option.
Our Range
The HS Auto Parts Ignition-Switched Kit Range
We’ve built our kits in-house, using quality Australian-made Tycab cable and genuine Anderson connectors, with everything pre-assembled by our auto electricians. You’re not buying a bag of loose parts — you’re getting a complete, tested kit that’s ready to fit.
Single Anderson Plug Kits — 7 Metre
Our 7-metre kits suit most dual-cab utes and 4WDs with a standard towbar setup. Both include a 100A ignition-controlled isolator relay, genuine 50A Anderson plug with flip-down cover, MIDI fuse and holder, conduit, mounting bracket, and two Add-A-Circuit fuse tap options.
7m 6 B&S 100A Ignition Controlled Isolator Kit
Suits BCDC chargers, lithium battery systems, and high-demand setups. 6 B&S cable rated to 89A continuous.
Shop 7m 6 B&S Kit →7m 8 B&S 100A Ignition Controlled Isolator Kit
The 8 B&S version runs 59A continuous — more than enough for most AGM-based caravan setups. Reliable, cost-effective choice.
Shop 7m 8 B&S Kit →Single Anderson Plug Kits — 6 Metre
If your tow vehicle is shorter — a single-cab ute, wagon, or canopy setup — the 6-metre kits cover most installs without excess cable to tuck away.
6m 6 B&S Anderson Extension Lead inc Ignition Sensing Relay
Higher-capacity 6 B&S cable with ignition-switched relay. Suits shorter wheelbase and high-demand charging systems.
Shop 6m 6 B&S Lead →6m 8 B&S Anderson Charging Lead inc Ignition Switched Relay
8 B&S cable with ignition relay — the practical choice for most standard AGM setups in a shorter vehicle.
Shop 6m 8 B&S Lead →AL-KO ESC
AL-KO ESC: It Needs Its Own Dedicated Run
If your caravan is fitted with an AL-KO Electronic Stability Control (ESC) system, the ESC requires its own independent, direct-from-battery power supply. It cannot share a circuit with your BCDC charger or other accessories.
This is a manufacturer requirement — and it catches a lot of people out.
Why a dedicated run?
The AL-KO ESC draws current whenever it's monitoring wheel speed and stability — which is constantly, while you're moving. Sharing a circuit with a DC-DC charger that also draws significant current can cause voltage drop that affects ESC response. AL-KO specifies a direct, dedicated feed from the vehicle battery for reliable operation.
AL-KO ESC Run — to Anderson Plug
For caravans with a red Anderson inlet on the A-frame. Includes 8m 6mm Tycab cable, 30A Cole Hersee auto-reset circuit breaker, split loom conduit, cable ties, lugs, heatshrink.
Shop ESC Run to Anderson →AL-KO ESC Run — to 12 Pin Plug
Delivers the ESC feed via the 12-pin plug. Same quality components — different termination. Auto-reset circuit breaker, no fuse to replace.
Shop ESC Run to 12 Pin →Cable Selection
6 B&S or 8 B&S — Which Cable Do You Need?
This is the most common question we get about these kits. The short version: choose based on your charger’s output current, not what seems “bigger is better.”
| Cable | Cross-section | Continuous rating | Best for |
|---|---|---|---|
| 8 B&S | 7.71mm² | ~59A | AGM dual battery, most standard setups |
| 6 B&S | 13.5mm² | ~89A | Lithium, DC-DC chargers 40A+, longer runs |
If your setup includes a BCDC1240D, Redarc Manager 30, or similar DC-DC charger drawing 20–40A, 8 B&S is fine. If you’re running a 40A+ lithium charger or have an unusually long run, step up to 6 B&S.
Our Tycab cable selection guide covers this in more detail if you want to dig into the numbers.
Installation
Why a Clean Mount Matters
A properly installed Anderson plug doesn’t just work well — it looks like it belongs there.
Our kits include an Anderson plug mounting bracket that bolts alongside your existing trailer socket, giving you a neat, factory-style finish with a protective flip cover on the plug. No exposed connectors rattling around under the bumper.
A loose or unprotected Anderson plug picks up road grime, vibrates against the bodywork, and eventually fails to make a reliable connection. A mounted, covered plug stays clean and positive-contact every time.
The Add-A-Circuit Question — Sorted
The trickiest part of fitting an ignition-switched Anderson plug is finding a clean ignition signal inside the cabin. Our 7-metre kits include both a MIDI fuse tap and a micro fuse tap — the two most commonly used Add-A-Circuit formats across modern 4WDs and utes.
If you’re comfortable reading a fuse chart and pulling a fuse box cover, you can pick up an ignition-switched signal without touching a single factory wire.
From the Workshop
From the Workshop
Every kit we sell is pre-assembled and tested by our team before it goes out. The components are the same ones we use in our own workshop installs — quality Tycab cable, genuine Anderson connectors, and fusing that’s properly rated for the circuit.
If you’re unsure whether you need a 6-metre or 7-metre kit, or whether your setup calls for 6 B&S or 8 B&S, give us a call. We’d rather spend five minutes helping you get the right kit than have you ordering twice.
Related Reading
Working Through a Full Tow Vehicle Electrical Setup?
These cover the rest of the system:
- Anderson Plug Kits — How to Choose
The full breakdown of kit types: ignition-switched, voltage-sensing, constant power, and ESC - Anderson Plug Extension & Adapter Leads
In-house extension leads and colour adapters for when your plug colours don’t match - Tycab Cable — How to Select the Right Gauge
B&S vs mm², amp ratings, and which cable for which job - 12V Cable for 4WD and Caravan
Twin core vs single core, and when to use each - Automotive Fuses — How to Choose
MIDI, ANL, blade fuses and when circuit protection matters - Portable Brake Controllers
The other towing upgrade people forget
Not Sure Which Kit Is Right for Your Setup?
Give us a call or drop us an email — our team is happy to point you in the right direction.
