P0147 Code

My service engine light is on (1996 Silverado, 5.0 L engine). Ran scan with an OBD ll meter and P0147 code shows up. Code description: O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 3.

Would someone please tell me which sensor this is. My Haynes Repair Manual does not provide enough detail. Also, is this a sensor I want to try and replace myself. Thanks

Its the oxygen sensor between the cat and the muffler, not a big job to replace

if u got the money replace them all