Passenger floorboard is soaked. I know its the heater core. Its the front one , isnt it? This is what rock auto sent me

2003 Tahoe LS

 

Looks like. On the GMT-400 pickups, you could change it without tearing the dash apart. The Climate Control Box had a removable bottom section. It was a tight job, but easier then tearing the dash apart. The earlier ones had crimped-on plastic tanks with plastic tubes, and could leak easy. The replacements had full metal, with no plastic at all. Don't know if that's possible in a 2003 Chevy Tahoe, but It's likely that the control box is not the same at all. The GMT-400's had no cabin air filter for instance.