99 blazer 4. something automatic changed both ho2 sensors after cat but still getting these dtc's. bank 1 sensor 3 is that the diver side or passenger side. narrowing it down to a bad wire or ground . where is this ground that is under the hood and can i bypass or jumper the bad wires?

 

Bank 1 is the driver side bank, however, B1S3 is the post cat sensor. You shouldn't have replaced any sensors that were ahead of the cat...

The B1S3 O2 sensor grounds to the back of the passenger side cylinder head.

Wiring is shown in the P0146 - HO2S Circuit Insufficient Activity Bank 1 Sensor 3 thread.

 

Thanks i'll give this another shot. by the way i changed a 20 amp fuse under the hood to 02 sensors can that mean another problem ?