Circuit Operation

The Converter Overtemp Alarm Module is powered at terminal A through fuse 1B and CKT 539 when the ignition switch is in RUN, BULB TEST Or START. The module is grounded at terminal B through CKT 1450 to ground G201. The module monitors the output signal of the converter Temperature Sensing probe at terminals C and D through CKTS 1790 and 1789. When the module detects that the Catalytic Converter temperature is excessive, it applies battery voltage to terminal E at CKT 558, which energizes the coil of the Converter Overtemp Alarm Relay.

The relay contacts close, connecting CKT 1345 through the relay contacts to ground G201 at CKT 1450. Current flows through fuse 9C, through CKT 40 and through the CONVERTER OVERTEMP indicator to the grounded CKT 1345; the CONVERTER OVERTEMP indicator turns on.