Downstream O2 sensor not getting 12v?

[JohnKimble]

Hello,

New here due to an issue that came up with my truck. 2006 GMC Sierra 1500 5.3. Couple days ago I got a check engine light. Scanned it and it came back Bank 1 Sensor 2 heater malfunction. I replaced both O2 sensors, took it for a drive...same issue.

I checked resistance in both O2 sensors, both within range. I checked voltage on the connector itself. Passenger side read 12v, drivers side...nothing. I checked both O2 sensor fuses, both okay. Both fuses are reading 12v as well. I removed the pink wire from the connector and inspected it, appeared fine with no damage whatsoever. Still tests 0v.

The underside of this truck is clean and the wiring harness (from what I can see under the truck) is unscathed. Where else should I be looking. Does this 12v from the drivers side O2 go directly from the connector to that fuse?

Any suggestions is appreciated!

[anumber1]

It is possible that there is corrosion in the fuse block.

 

It's worth a try to pull the fuse, squirt a bit of contact cleaner and make sure the blades of the fuse are clean and bright.

[JohnKimble]

I believe O2B fuse is the downstream, so since this circuit is providing power to the passenger side downstream sensor, I'm led to believe the connection at the fuse block is good?

[JohnKimble]

Turns out the wiring loom above the driveshaft was rubbing against a bracket of sorts. Dealership got me $230 for that one.