2018 Silverado--power feed to EVAP vent?

[D60]

2018 Silverado 1500 with 5.3. I'm not getting any voltage to red/grn wire at EVAP vent. White wire switches ground when commanded.

I can't determine where this gets power for 2018? Earlier trucks supposedly had a fuse underhood, and 2019+ is apparently given power from fuel pump module. Is that also the case here, ie fuel pump module?

All wiring appears good from what I can see (without tearing into the main framerail loom)

@clinebarger

 

[MrHorspwer]

Fuse 57 in the underhood fuse block. It is a three-legged fuse.

 

[D60]

Fuse 57 in the underhood fuse block. It is a three-legged fuse.

Ok, thank you. Shows as TCM/ECM, which I understand these descriptions are not exhaustive. Checks out ok at all three terminals unfortunately. So something else is causing lack of power to vent electrical connector.

 

[GMBoy]

I am also showing Fuse 57 as the power fuse for that wire.

 

[D60]

Thank you all. So does anyone know what switches power to that wire? I mean is it just hot with ignition all the time, or can a module revoke the power for some reason?

Also from the EVAP vent pigtail, does that wire travel forward toward the underhood fuse box, or rearward toward maybe a fuel pump module?

 

[D60]

I finally had time to revisit this P0449 on this '18 Silverado 1500.

I was still not getting power on the red/grn wire. There was also no power where the pigtail branched off from the larger harness along the framerail.

I hacked in under the driver door at a location with easy access and BAM! power! I decided against trying to find the exact location of the fault and just did an overlay.