This are the underhood relay and fuse boxes. There are three of them on 1Gs, and one on 2Gs. Stock cars will not normally have black wires going to the mounting screws of the boxes. Not all cars will have all fuses and relays installed; for more information refer to the factory electrical manual.

For 1Gs, each box has a specific name. The smallest one, that holds three or four fuses, is called the main fusible link box, and connects directly off of the positive post of the battery. The other boxes are called sub fusible links.

The small one in the left-hand picture holds the MPI fuse. This is the fuse normally removed when doing compression tests or other tests where you need to crank the engine over without allowing it to start. Removing this fuse will also erase the ECU memory, clearing any error codes in the ECU.

The fuses and relays are marked according to function. Problems with the fuse or relay can cause the marked systems to fail to operate correctly. Fuses are marked with an amperage (A) rating - relays are not. Unless otherwise noted the fuses and relays connect 12 volt power to the indicated devices.

• Driver's side relay box
  • A/C FAN (Hi-Lo): Air conditioner condensor high/low relay.
  • A/C COND. FAN: Air conditioner condensor fan relay.
  • A/C CLUTCH: Air conditioner magnetic clutch relay.
• Passenger side small relay box
  • IGN = Ignition switch fuse.
  • RAD FAN = Radiator fan fuse.
  • MPI = Multi-point ignition system.
  • ABS = Anti-lock braking system fuse.
• Passenger side large relay box
  • ALT = Alternator (relay and fuse).
  • RAD FAN = Radiator fan, connecting power to the fan.
  • FOG = Fog lights (if equipped, relay and fuse)
  • WDO = Power window fuse.
  • HEAD = Headlights.
  • TAIL = Tail lights (relay and fuse).
  • ??? = Pop-up headlight motor relay.
  • HAZARD = Hazard lights.
  • LAMP = Multiple connections: buzzers, door locks, theft alarm, back-up lights, fan, etc.
  • HI-BEAM = High-beam headlights.
  • R. DEF = Rear window defroster fuse.
  • BELT = Automatic seatbelt fuse.
  • ALT SENS = Pop-up headlight fuse (if equipped) and alternator.
  • BAT = Multiple connections: buzzers, automatic seatbelts, air conditioner, heater, power windows, etc.

  (C) 2004-2007 Sean Costall