This guide offers clear, visual documentation for all power distribution points on your Isuzu Forward truck:
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Fuse Box Locations: Clear identification of all fuse and relay panels, including the primary boxes in the cab interior (under the dash/side panel), and the engine bay main power center.
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Circuit Identification: Detailed diagrams showing the number, amperage (rating), and primary function (e.g., "ECM Power," "Tail Lamp," "ABS System") of every single fuse.
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Relay Functions and Pinouts: Clear labeling and diagrams identifying the function and control circuit for all major relays (e.g., Main Power Relay, Starter Relay, Headlamp Relays).
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High-Current Breakers: Information regarding the location and rating of main circuit breakers protecting high-draw systems.
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Model Specificity: Documentation is tailored specifically to the electrical system architecture of the 2007–2016 model years, covering common engine configurations during this period.
Fuse box in the passenger compartment
| No. | A | Function Description |
| 1 | 20 | Headlight Cleaner / Headlamp Washers |
| 2 | 15 | Air Suspension |
| 3 | 15 | Cabin Lighting / Interior Lamp |
| 4 | 15 | Door Locks |
| 5 | 10 | Front Fog Lamps |
| 6 | 20 | Power Windows / Electric Window Regulators |
| 7 | 10 | Anti-lock Braking System (ABS) |
| 8 | 20 | Windshield Wipers and Washers |
| 9 | 10 | Left Headlight / Left Headlamp |
| 10 | 10 | Immobilizer |
| 11 | 10 | Right Headlight / Right Headlamp |
| 12 | 10 | Stop Lamps / Brake Lights |
| 13 | 10 | Starter |
| 14 | 10 | Left Headlight / Left Headlamp |
| 15 | 10 | Right Headlight / Right Headlamp |
| 16 | 15 | Mirror Heater / Defroster |
| 17 | 15 | Air Dryer |
| 18 | 15 | Power Take-Off (PTO) Mechanism. Reverse Lamp / Backup Light |
| 19 | 10 | Airbags / Supplementary Restraint System (SRS) |
| 20 | 10 | 6HK1, 4K1: Auxiliary (Engine) Brake |
| 21 | 10 | 6HK1, 4K1: Engine Control Unit (ECU) |
| 22 | 10 | 6HK1, 4K1: Gauges / Instruments, Control Unit |
| 23 | 10 | 6HK1, 4K1: Headlights, Rear Lamps (Relay) |
| 24 | 10 | 6HK1, 4K1: Right Rear Fog Lamp |
| 25 | 15 | Electric Mirror Adjustment |
| 26 | 15 | Cigarette Lighter / Power Outlet |
| 27 | 15 | Horn |
| 28 | 10 | Turn Signals, Hazard Warning Lights |
| 29 | 10 | Rear Lamps / Taillights |
| 30 | 10 | Lighting |
| 31 | 10 | Cornering Lamp / Right Rear Fog Lamp |
| 32 | 20 | Heater Fan / Blower Motor |
| 33 | 20 | Condenser Fan (Air Conditioning) |
| 34 | - | Spare Slot / Reserved |
| 35 | 15 | 6HK1, 4K1: Power Windows (Rear) Right-Hand Drive (RHD) Models |
| 36 | 25 | 6HK1, 4K1: Anti-lock Braking System (ABS) |
| 37 | - | Spare |
| 38 | - | Spare |
| 39 | - | Spare |
Isuzu Relay Assignment
| No. | Relay Function Description |
| 1 | Stop Lights / Brake Lights |
| 2 | Heater Fan / Blower Motor |
| 3 | Ignition Lock (ON Position) |
| 4 | 6HK1, 4K1: Door Locks (Locking) |
| 5 | 6HK1, 4K1: Rear Fog Lamp |
| 6 | Wipers (Primary Mode) |
| 7 | Horn |
| 8 | Wipers (High/Low Speed Modes) |
| 9 | Fog Lights |
| 10 | 6HK1, 4K1: Headlight Cleaner / Headlamp Washers |
| 11 | 6HK1, 4K1: Door Locks (Unlocking) |
| 12 | Power Windows / Electric Window Regulators |
| 13 | Headlight (Low Beam) |
| 14 | Manual Transmission (MT): Engine Operation (with HSA System) |
| Manual Transmission (MT): Engine Operation (without Smoother System) | |
| Automatic Transmission (AT): Reverse Gear | |
| 15 | FVZ, GVR (Thailand): Trailer Stop Lights |
| Headlight (High Beam) | |
| 16 | Rear Lamps / Taillights |
| 17 | 6NN1, 6HK1, 4K1: Main Power Take-Off (PTO) Mechanism (Models with PTO) |
| 6HK1, 4K1: Trailer Rear Lights | |
| 18 | 6HK1, 4K1: Ignition |
| 6NN1: Power Take-Off (PTO) Mechanism Disengagement (Models with PTO) | |
| 6HK1, 4K1: Auxiliary Equipment | |
| 6HK1, 4K1: A/C Condenser Fan | |
| 19 | RHD (Thailand): AT (6HK1, 4K1): Auxiliary (Engine) Brake Indicator Disengagement |
| FVZ, GVR (Thailand): Trailer Reverse Lamp (6HK1, 4K1) | |
| 20 | RHD (Thailand): AT (6HK1, 4K1): Auxiliary (Engine) Brake Control (Automatic Transmission Models) |
| RHD (Thailand): Trailer Stop Lights (6HK1, 4K1) | |
| 28 | RHD (Thailand): Ignition (6HK1, 4K1) |
Relay box in the passenger compartment
| No. | Relay Function Description |
| 20 | 6NN1: Auxiliary (Engine) Brake Control |
| AT: Auxiliary (Engine) Brake Disengagement | |
| 21 | 6HK1, 4K1: Main Power Take-Off (PTO) Mechanism |
| Models with PTO: Main Power Take-Off (PTO) Mechanism | |
| with ABS (Thailand): Ignition | |
| A/C Condenser Fan | |
| 22 | 6HK1, 4K1: with ABS (Thailand): Auxiliary Equipment |
| FSS, FTS (6NN1): Transfer Case (LOW) | |
| 23 | 6HK1, 4K1: Models with MT and PTO: Power Take-Off (PTO) Mechanism Disengagement |
| 6HK1, 4K1: AT: AT Neutral | |
| FVZ, GVR (Thailand): Trailer Stop Lights | |
| 6HK1: Front Axle Differential Lock | |
| 24 | 6HK1, 4K1: with ABS (Thailand): Auxiliary (Engine) Brake Control |
| 25 | - |
| 26 | - |
| 27 | 6HK1, 4K1: All-Wheel Drive (AWD): Transfer Case (LOW) |
| 6HK1, 4K1: ABS: Auxiliary (Engine) Brake Control | |
| 28 | Models with PTO: Main Power Take-Off (PTO) Mechanism |
| 29 | 6HK1, 4K1: Trailer Hazard Warning Lights |
| 30 | 6HK1, 4K1: Trailer Information 1 |
| 31 | 6HK1, 4K1: Rear Electric Power Windows |
| FVZ, GVR (Thailand): Trailer Stop Lights | |
| 32 | FVZ, GVR (Thailand): Trailer Rear Lamps |
The fuse box is located on the left side behind the cabin.
| No. | A (Amperage) | Function Description |
| Fuses | ||
| 1 | 15 | 6HK1, 4K1: Engine Control Module (ECM) |
| 2 | - | - |
| 3 | - | - |
| 4 | - | - |
| 5 | 10 | Air Conditioner |
| 6 | 10 | 6NN1: Engine Stop |
| 7 | 15 | Power Source |
| 8 | 15 | 6HK1, 4K1: Transmission Control Module (TCM) |
| Relays | ||
| 1 | 6HK1, 4K1: Starter | |
| 6HK1, 4K1: Fuel Heater | ||
| 2 | 6HK1, 4K1: Engine Control Module (ECM) | |
| 3 | Preheating / Glow Plug System | |
| 4 | Electromagnetic Clutch | |
| 5 | 6HK1, 4K1: Buzzer Disengagement / Disconnect | |
| 6HK1, 4K1: Load | ||
| 6 | 6HK1, 4K1: Starter Disengagement / Disconnect | |
| 6NN1: Engine Stop | ||
| 7 | 6HK1, 4K1: Stop Lamp Control |
2016 Isuzu Truck
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