Power On Demand:
The EXT & INT Port System

Lighting Strategy:
Putting the Circuits to Work

The Grenadier's EXT system doesn't just supply power — it supplies the right power in the right locations for a complete exterior lighting build. Four of the five exterior circuits (EXT1, 2, 3, and 5) are positioned and rated specifically for lighting applications. Here's how a well-planned build maps across the system.

Forward Lighting — EXT1 & EXT5

Both under-hood circuits serve the front of the vehicle. EXT1's 10-amp circuit handles a pair of small LED pods or ditch lights comfortably — accessories drawing 6–8 amps total. For higher-output forward lighting — a triple-pod bumper bar kit, high-powered driving lights, or anything above 120W — move to EXT5's 25-amp circuit. The two circuits give you independent switching for layered forward lighting: low-power spots on EXT1 for daily use, high-output floods on EXT5 for trail work.

Rooftop Light Bar — EXT2

EXT2 exists for one primary purpose: powering a rooftop light bar with a dedicated, unshared 25-amp circuit. A high-output 40–50 inch LED bar typically draws 15–22 amps. On EXT2, that load runs on its own fused circuit with no competition from other accessories, no voltage drop from shared wiring, and no risk of overloading a multi-device circuit. The DTP connector at the roofline means the bar plugs directly into factory wiring — no penetrating the roof, no routing cable through the headliner, no aftermarket relay harness.

Scene & Work Lighting — EXT3

EXT3's three distributed DTP ports turn the Grenadier's roofline into a multi-zone scene lighting platform. Mount a pair of downward-facing flood lights above the driver's side doors for camp lighting, add a rear-facing work light above the passenger-side rear door for load area illumination, and switch all three on with a single rooftop toggle. The shared 25-amp circuit means you need to budget your total draw, but three 60W flood lights (180W total) leave room to spare.

Why This System Matters

Every serious overlanding build starts with the same problem: getting power from the battery to wherever you need it. On most vehicles, that means hours of routing wire through grommets, firewall penetrations, and body panels — work that's tedious, error-prone, and often ugly. Aftermarket relay harnesses solve part of the problem, but they still require custom routing and fuse panel installations.

The Grenadier's EXT system eliminates this entire category of work. The wiring is already routed. The fusing is already done. The switching is already installed in the overhead console. What would be a full weekend of wiring on a Land Cruiser or Wrangler becomes a plug-and-play installation on the Grenadier — often measurable in minutes rather than hours.

The use of Deutsch DTP connectors on the roofline ports is a deliberate engineering decision, not a cost-saving one. DTP connectors cost more than commodity 12V sockets, but they're rated for the vibration, moisture, and thermal cycling that rooftop-mounted accessories actually experience. A standard SAE or cigarette-lighter connector at the roofline would be a reliability problem within months. DTP connectors are a solve-it-once decision.

The mix of unterminated pigtails and DTP ports reflects a clear design philosophy: give structured, plug-and-play power where plug-and-play makes sense (the roofline), and give open-ended flexibility where customization is expected (the engine bay, the wheel well). It's the kind of decision-making that suggests the engineers actually bolt accessories onto trucks — and have opinions about how it should work.

Roof Switch Integration

Every EXT circuit is controlled from the overhead switch panel — the same aircraft-inspired control surface that manages the Grenadier's differential locks, center locking, and interior lighting. The switches are large, clearly labeled, and designed to be operated with gloved hands. There's no fumbling for a hidden toggle under the dash or reaching for an aftermarket switch pod bolted to the A-pillar.

The switching architecture is simple and deliberate: one switch per circuit. EXT2 gets its own switch. EXT3 gets its own switch — and that single switch controls all three of its distributed DTP ports simultaneously. This is camp-lighting logic: one flip illuminates your entire perimeter. For layered lighting control across all circuits, you have independent switches for each zone of the vehicle, all within reach without taking your eyes off the trail or leaving the driver's seat.

The integration with the roof-mounted switch panel also means these circuits are visually and operationally consistent with the rest of the vehicle's controls. There's no jarring aftermarket aesthetic — no toggle panels zip-tied to the center console, no loose switches velcroed to the dash. The EXT switches look and feel like they belong, because they do.

What Owners Actually Plug In: Real-World Circuit Usage

Forum discussions and owner builds reveal clear patterns in how the EXT and INT circuits get used in practice. Here's what the community has settled on after thousands of collective kilometres:

EXT1 (Engine Bay, 10A) — The Light Pod Circuit

The most common use: a pair of small LED pods mounted to the front bumper or A-pillars. At 10 amps, this circuit handles most LED pods comfortably — a typical pair of 20W pods draws under 4 amps total. DVA's front bumper light mounts use this circuit for forward-facing spot or flood pods, keeping the wiring clean and factory-integrated. Some owners use EXT1 for a single ditch light or a small compressor, but lighting dominates.

EXT2 (Roof, 25A) — The Light Bar Circuit

Almost universally dedicated to a roof-mounted light bar. The 25-amp capacity handles anything up to a 40-inch LED bar. DVA's LED Roof Light Bar is designed specifically for this circuit, drawing well within the 25A budget while delivering serious forward illumination. A few owners split this circuit to run a light bar plus a small Starlink dish power feed, but that requires careful amperage math.

EXT3 (Roof, 25A) — Scene Lighting and Side Lights

The versatile circuit. Forum owners most commonly use EXT3 for side-mounted scene lights — illuminating the campsite, the work area beside the truck, or reverse lighting for trailer hookup. DVA's side-mount LED pods (available in spot or flood) connect here via DTP connectors. Some owners run four side lights (two per side) on this single 25A circuit without issues, as LED pods are remarkably efficient.

EXT4 (Wheel Well, 500A) — Winch Only

This is the winch circuit. 500 amps. Nothing else should connect here unless you're deliberately running a high-draw accessory through the factory winch relay system. Forum consensus: leave this alone unless you have a winch.

EXT5 (Engine Bay, 25A) — The High-Power Forward Circuit

Owners who need more forward lighting power than EXT1's 10 amps use EXT5 for larger LED bars, driving lights, or onboard air compressors. DVA's front bumper light system can also wire to EXT5 when running higher-output pods. This is also the circuit of choice for owners adding a secondary horn, high-output fog lights, or an underhood compressor for onboard air.

INT1 & INT2 (Footwells, 10A each) — Interior Accessories

Phone chargers, dash cameras, ham radios, and interior LED strips. INT2 is popular for powering a fridge in the rear cargo area, though owners running large 12V fridges should verify the draw stays under 10 amps (most do, but dual-zone units at startup can spike). Some owners use INT1 for a CB/ham radio and INT2 for a rear dashcam and interior lighting.

Common Mistakes with the EXT/INT System

The forum community has documented these errors repeatedly. Learn from their experience:

Overloading EXT1

EXT1 is rated at 10 amps — not 25. Owners who wire a light bar to EXT1 because it's the "easiest to access" will trip the fuse or, worse, overheat the wiring harness. If your accessory draws more than 8 amps continuous, use EXT5 or EXT2 instead. A relay triggered by EXT1 feeding from a higher-capacity circuit is the correct approach for accessories that exceed 10A.

Using Wrong Connector Types

The Grenadier uses two connector standards: unterminated pigtails (for EXT1, INT1, INT2) and Deutsch DTP connectors (for EXT2, EXT3). Forum posts show owners trying to splice into these pigtails with butt connectors or scotch locks — both of which fail in engine bay environments due to heat and vibration. Use the correct mating connectors for reliable long-term connections.

Daisy-Chaining Accessories on One Circuit

Just because a circuit has capacity doesn't mean you should chain five accessories off it. Every splice is a potential failure point, and voltage drop across multiple connections degrades performance. One circuit, one primary accessory (or one properly wired distribution point) is the reliable approach.

Ignoring the High-Load Panel Requirement

EXT2 through EXT5 require the optional High-Load Auxiliary Switch Panel. Without it, you only have EXT1, INT1, and INT2. Owners who buy a 25A-rated light bar and then discover they don't have EXT2 face an expensive retrofit. Check your overhead switch panel before ordering accessories — if you see only one auxiliary switch, you have the base configuration and need the High-Load Panel upgrade.