Charging System: Testing and Inspection

- Circuit A21 splices to supply battery voltage to the coil side of the ASD relay and the fuel pump relay. If battery voltage is not present on the A21 circuit at the ASD relay, the PCM will not be able to energize the relays. The ASD relay supplies battery voltage for the fuel injectors, ignition coil, and the heated oxygen sensor. The fuel pump relay powers the fuel pump module.
- Ground circuit Z1 also supplies ground for the A/C compressor clutch.