Box Diagram - 1994 Freightliner Fl80 Fuse

| Relay | Function | | :--- | :--- | | K1 | Starter relay | | K2 | Heater blower high-speed relay | | K3 | A/C compressor clutch relay | | K4 | Daytime running lights (if Canadian spec) | | K5 | Trailer stop/turn isolation relay |

While there is a fuse for the ABS (usually 20A), the 1994 FL80 often had an ABS relay located in a separate "relay box" near the main fuse panel. If the ABS light stays on, check the fuse first. If the fuse is good, check the wheel speed sensors located at the wheels for debris or broken wires.

If you plan to keep your FL80 on the road for another decade, consider these upgrades: 1994 freightliner fl80 fuse box diagram

The panel usually contains glass fuses (ATO/ATC style) for standard circuits and metal strip circuit breakers for heavy-duty applications (like wipers and lights).

| Position | Circuit / Function | Amp Rating | Description | | :--- | :--- | :--- | :--- | | 1 | Turn Signals | 20A | Controls the left and right turn signal flashers. | | 2 | Backup Lights | 15A | Powers the reverse lights when the transmission is in reverse. | | 3 | Stop / Brake Lights | 20A | Powers the brake lights at the rear of the cab and trailer connection. | | 4 | Horn | 20A | Powers both the city horn and the air horn solenoid (if equipped). | | 5 | Heater / A/C Blower | 25A | Powers the fan motor for the HVAC system. | | 6 | Cigarette Lighter / Accessory | 15A | Powers the cigarette lighter and often the radio memory/power. | | 7 | Wiper / Washer | 20A (Breaker) | Often a circuit breaker. Powers the windshield wiper motor and washer pump. | | 8 | Instrument Cluster | 10A | Powers the gauges (speedometer, fuel, voltmeter) and warning lights. | | 9 | Dome / Cargo Light | 15A | Interior cab lighting and optional cargo area lighting. | | 10 | Headlight High Beam | 20A | Specifically for the high beam headlight circuit. | | 11 | Headlight Low Beam | 20A | Specifically for the low beam headlight circuit. | | 12 | Park / Marker Lights | 20A | Front and rear running lights, side markers, and license plate light. | | 13 | Radio / Stereo | 10A | Powers the aftermarket or factory-installed radio. | | 14 | Dash Lights | 10A | Illumination for the dashboard gauges and switches. | | 15 | ECM / Engine Control | 10A or 15A | Powers the Engine Control Module (computer). Do not remove while running. | | 16 | Cruise Control | 10A | Powers the cruise control servo and dashboard switch. | | 17 | Fuel Heater | 15A | (Cold weather models) Powers the heating element in the fuel filter/water separator. | | 18 | ABS Power | 20A | Powers the Anti-lock Braking System module. | | 19 | Accessory Power | 20A | Often used for additional equipment or 12V power points. | | 20 | Starter Solenoid | 10A | Signal wire to the starter solenoid. | | Relay | Function | | :--- |

Note: Slots labeled "Spare" in your specific box are open terminals for adding accessories.

Before you can use a diagram, you need to find the box. On a 1994 FL80, there are three possible locations: While there is a fuse for the ABS

If nothing turns on when you turn the key:

| Fuse # | Amp | Circuit / Component | |--------|-----|----------------------| | 1 | 30 | Ignition switch feed | | 2 | 15 | Turn signals / flasher | | 3 | 10 | Instrument cluster lights | | 4 | 20 | Windshield wipers | | 5 | 15 | Heater blower motor | | 6 | 10 | Clearance/marker lights | | 7 | 20 | Stop lamps | | 8 | 15 | Backup lights | | 9 | 30 | Power windows (if equipped) | | 10 | 10 | Radio / Cigar lighter | | 11 | 20 | Trailer running lights | | 12 | 15 | A/C clutch | | 13 | 20 | Headlight dimmer relay | | 14 | 10 | ABS control module power | | 15 | 15 | Cruise control | | 16 | 30 | Starter relay |

Note: Amps and assignment vary. Always verify with your truck’s diagram.

Due to the age of the 1994 Freightliner FL80, many original owner’s manuals and fuse box cover stickers have faded or disappeared. Here are your best alternatives: