E. Pre-Excitation Resistor (or Relay)

The generator produces electricity by creating a magnetic field in the stator & rotor. When a vehicle is first started, this magnetic field must be initiated (pre-excitation). Once the initiation has started and the generator begins producing output with sufficient voltage (more than battery voltage), the generator provides self-excitation. Thus, the pre-excitation circuit (including the pre-excitation resistor/relay) is only required during the generator output initiation phase.

If the pre-excitation resistor malfunctions, the pre-excitation circuit may not function properly and generator initiation may not occur, in which case, the generator will have no output. Thus, if a generator has no output, swap the pre-excitation resistor/relay with a known good unit and check again for output in order to confirm or eliminate the pre-excitation circuit as a possible cause.

Location of the pre-excitation resistor:

Vehicle Location

Accent (SOHC) On the dash panel near the centerline of the vehicle
Elantra/Tiburon In the engine compartment fuse box

Sonata (V6 & 14) On the dash panel on the passenger side above the brake booster