Ignition Coil Power Supply

Though the power supply to the ignition coils is not an output function of the engine control module, it must be considered during diagnosis. Up to 1996 model year, the ignition coils received their operating power directly from the the KL 15 ignition switch terminal.

Starting with the 97 model year the power supply for the ignition coils is provided by a relay. This relay is identified as an "unloader relay" in the ETM and component listing displays.

The purpose of this relay is to isolate the voltage supply as well as relieving the ignition switch of the additional current draw needed by the ignition coils.

When KL 15 is switched on, the relay control circuit is provided power to close the relay providing operating voltage to ignition coils.