Volvo FH12 Geartronic Wiring Diagram PDF | Complete Electrical System Schematics

The Volvo FH12 Geartronic Wiring Diagram Manual PDF provides the complete electrical system layout for Volvo FH12 heavy-duty trucks equipped with the Geartronic automatic transmission.
This technical reference includes full power distribution diagrams, switch functions, grounding points, CAN bus connections, and ECU interfaces—ideal for service technicians and electrical engineers working on troubleshooting or retrofitting Volvo heavy vehicle systems.

The manual illustrates all signal paths with labeled connectors, cables, and fuses following the official Volvo Group electrical symbol system, ensuring precise diagnostics and maintenance.

Technical Highlights

• Full Geartronic transmission control wiring diagram

• Battery, ignition, and power supply circuits

• CAN communication network layout (engine, gearbox, and dashboard modules)

• Sensor, switch, and actuator pinout references

• Fuse and relay location tables

• Grounding and joint-sleeve maps

• Component legend with official Volvo electrical symbols

Table of Contents

• Component wiring diagrams
  • Power supply, starting system, immobiliser
  • Vehicle ECU
  • Engine ECU, fuel injection system, preheating, FH12
  • Head light, parking light, marker light, DRL
  • Fog light, rear fog light
  • Spot light (STD) DRIVL2
  • Spot light (EU) DRIVL2EC
  • Brake light
  • Trailer controlled exhaust brake
  • Direction indicator, hazard warning light
  • Reversing light, reversing warning alarm
  • Loading light, fifth wheel light
  • Roof sign light, L1H1/L2H1
  • Roof sign light, L2H2
  • Beacon warning light
  • Interior light, L1H1/ L2H1, alarm clock/timer
  • Interior light, L2H2, alarm clock/timer
  • Cigarette lighter
  • 12 V power supply
  • Horn
  • Wiper, washer
  • Climate unit
  • Cab heater, EBERSPÄCHER D1LCC, PH-CAB
  • Cab and engine heater, WEBASTO THERMO 90, PH-ENGCA
  • Electrically heated and adjusted seat
  • Electrically heated mirrors
  • Electrically operated mirrors
  • Air dryer
  • Fuel filter heater
  • Water separator heater
  • Electrically cab tilt
  • Radio
  • Electrically operated window winders
  • Electrically sunroof
  • SRS, airbag
  • Central door lock
  • Power take-off
  • Double power take-off
  • Differential lock
  • Bogie lift, tag axle lock, RADT-LA
  • Tag axle lock, RADT-A6S
  • Bogie lift hydraulic, RADT-AR
  • Bogie lift hydraulic, with axle load limiter, RADT-AR
  • Air suspension, 6x2/6x4/8x2/8x4, SUSPL-EC
  • Air suspension, 4x2, SUSPL-EC
  • Rear air suspension, 4x2, TRACTOR, SUSPL-EC
  • Instrument LHS module
  • Instrument central module with tachograph
  • Instrument RHS module
  • Instrument central module without tachograph
  • Basic ABS, D-version
  • ABS/ASR, D-version
  • Headlight level control
  • Refrigerator
  • Central lubrication system
  • Extra fuses, key switch relay
  • Earth connections
  • Earth connections
  • ADR battery main switch, current limiter
  • Air heater EBERSPÄCHER TMD, ADR-FRA
• Illustrations index
  • Earth connections
  • Battery cables
  • Windscreen wiper motor
  • Cable harness, instruments
  • Cable harness, tachograph (CABLE-EC)
  • Cable harness, cab, upper
  • Cable harness, cab, lower
  • Cable harness, cowl
  • Cable harness, engine
  • Cable harness, tail lights
  • Cable harness, air dryer
  • Cable harness, chassis
  • Cable harness, side marking lamp
  • Cable harness, door
  • Cable harness, cab, ABS
  • Cable harness, solenoid valve, ABS
  • Cable harness, windscreen washers
  • Cable harness, pulse sensor - tachograph (CABLE-B)
  • Cable harness, extension
  • Cable harness, electric heated rearview mirror
  • Cable harness, cab tilt pump
  • Cable harness, additional accessories
  • Cable harness, engine, cab
  • Cable harness, adapter, no tachograph
• Fuses on circuit card electrical centre
  • Air suspension/Hydralic bogielift (kl.DR)
  • Range-, area-inhibitors, compressor control
  • SRS airbag, Immobiliser
  • Central door lock
  • Interior light, timer
  • Brake light trailer
  • Instrumentation (kl.30)
  • Voltage divider for radio
  • Brake light truck
  • Spotlight
  • Fullbeam flash
  • Air suspension (kl.30)
  • Electric heated rearview mirrors
  • Preheating, relay/radiopos.
  • Dipped beam lhs
  • Fullbeam lhs, fullbeam indicator lamp
  • Radiopos. startswitch
  • Cooling fan control, preheat relay
  • Vehicle ECU
  • Engine solenoid valves
  • Instrumentation, electric heated mirror relay (kl.61)
  • DRL (day running light)
  • Electric heated airdryer
  • Extra equipment "XA", relay bodybuilder fusebox (kl.15)
  • Electric adjustable mirrors
  • Differential lock, power take off
  • Electronic climate control
  • Direction indicator, Instrumentation (kl.15)
  • Horn, solenoid valve for airhorn
  • Cigarette lighter, centre section storagelamp
  • Voltage divider for 12V. outlets
  • Foglight, rear foglight
  • Park. light truck lhs
  • Parking light trailer lhs
  • Bedlamps, luggage compartment lamp, bedlock
  • Parking light trailer rhs
  • Parking light truck rhs
  • Direction indicator, hazard warning light (kl.30)
  • Dipped beam rhs
  • Fullbeam rhs
  • Electric window winder, passenger side
  • Electric window winder, driver side
  • Engine ECU
  • Revers light, revers warning alarm
  • Fan, climate unit
  • Electric heated seat, parking heater
  • Windscreen wiper
  • Headlamp wiper, windscreen and headlamp washer
• Relays on circuit card electrical centre
  • Relay, fog lights “9”
  • Relay, reversing lights “12”
  • Relay, full beams “11”
  • Relay, dipped beams “12”
  • Relay, brake lights truck “8”
  • Relay, brake lights trailer “10”
  • Relay, parking lights lhs “1”
  • Relay, parking lights rhs “2”
  • Relay, starting switch “4”
  • Relay, rear fog lights “7”
  • Relay, fan, climate unit “13” (HA6)
  • Relay, power take off inhibitor “14”
  • Relay, fuel injection “5”
  • Alternator-controlled relay
  • Relay, interior lamps
• Cable harness illustration index
  • Windscreen wiper motor
  • Cable harness, instruments
  • Cable harness, tachograph (CABLE-EC)
  • Cable harness, cab, upper
  • Cable harness, cab, lower
  • Cable harness, cowl
  • Cable harness, engine
  • Cable harness, tail lights
  • Cable harness, air dryer
  • Cable harness, chassis
  • Cable harness, side marking lamp
  • Cable harness, door
  • Cable harness, cab, ABS
  • Cable harness, solenoid valve, ABS
  • Cable harness, windscreen washers
  • Cable harness, pulse sensor - tachograph (CABLE-B)
  • Cable harness, extension
  • Cable harness, electric heated rearview mirror
  • Cable harness, cab tilt pump
  • Cable harness, additional accessories
  • Cable harness, engine, cab
  • Cable harness, adapter, without tachograph

File Information

• Manufacturer: Volvo Trucks

• Model Coverage: Volvo FH12 / NH12 (Geartronic Transmission)

• System Covered: Electrical / Geartronic Control System

• Language: English

• Pages: 37

• Category: Electrical Wiring & Schematics