which is the signal wire on h02 sensor high or low
 

Hey all, Can anyone tell me on the ho2 sensor which wire is the true signal wire is it the high signal wire or the low signal, If I understand the schematic right it would be the low signal wire thanks for the help

This is a 2004 chevy silverado 5.3L eng

The voltage is measured on the high signal wire relative to the low signal wire which is at ground potential.