2003 Ford F150 Underhood Fuse Box Identification. Below you will find an image of the underhood or battery junction box. Each component is identified and there is a legend below. Clicking on the image will enlarge it.
Fuse Legend
1 (20A) – Power Point.
2 (30A) – PCM Power Relay.
3 (30A) – Main Light Switch, Headlamp Relay, Multifunction Switch.
4 (20A) – Power Point, Console.
5 (20A) – Trailer Tow Relay, Parking Lamp; Trailer Tow Relay, Reversing Lamp.
6 (15A) – Main Light Switch, Park Lamp Relay.
7 (20A) – Horn Relay.
8 (15A) – Central Security Module.
9 (15A) – Daytime Running Lamps Resistor, Fog Lamp Relay.
10 (20A) – Fuel Pump Relay.
11 (20A) – Generator.
12 (20A) – Power Point, Rear.
13 (15A) – A/C Clutch Relay.
14 (N/A) – Not Used.
15 (10A) – Running Board Lamps (Left Front & Rear, Right Front & Rear).
16 (15A) – Alternative Fuel Control Module (AFCM), Alternative Fuel Indicator Switch, Fuel Injectors.
17 (2A) – Brake Pressure Switch.
18 (15A) – Mass Air Flow (MAF) Sensor, Powertrain Control Module (PCM), Fuel Injectors 1-8, Idle Air Control (IAC) Valve, Fuel Pump Relay, Fuel Pump Cutoff Relay.
19 (10A) – Trailer Tow Connector.
20 (10A) – Trailer Tow Connector.
21 (N/A) – Not Used.
22 (N/A) – Not Used.
23 (15A) – Evaporative Emission (EVAP) Canister Vent Valve, EVAP Canister Purge Valve, Heated Oxygen Sensor (HO2S) #21, Heated Oxygen Sensor (HO2S) #11, A/C Clutch Relay, Heated Oxygen Sensor (HO2S) #22, Heated Oxygen Sensor (HO2S) #12, Automatic Transmission Module, Camshaft Position Sensor, Intake Manifold Runner Control (IRMC) Module, Bi-Fuel Power Relay.
24 (N/A) – Not Used.
101 (30A) – Trailer Tow Relay, Battery Charge.
102 (50A) – ABS Control Module.
103 (50A) – Central Junction Box (CJB).
104 (30A) – Transfer Case Relay Module, Transfer Case Electric Clutch Relay, Mechanical Shift on the Fly (MSOF) Relay.
105 (40A) – Blower Relay.
106 (20A) – Charge Air Cooler Pump Relay.
107 (N/A) – Not Used.
108 (30A) – Trailer Tow Connector.
109 (N/A) – Not Used.
110 (30A) – Accessory Delay Relay.
111 (40A) – Ignition Switch.
112 (30A) – Adjustable Pedal Switch, Power Seat Switch (left).
113 (40A) – Ignition Switch.
114 (N/A) – Not Used.
115 (20A) – Central Security Module.
116 (40A) – Rear Window Defrost Relay.
117 (40A) – Audio.
118 (30A) – Heated Seat Module (Driver & Passenger Front).
601 (30A) – Accessory Delay Relay.
602 (N/A) – Not Used.