Thank you, Steve. You saved me from digging.See the link below and scroll down to the second diagram (Engine Data Sensors - 5-volt and Low Reference). Dead center is the Camshaft Position sensor and it shows the wire colors for the 5v Ref #1 (D-BU) and the ground (BN). That 5V Ref is shared by a few sensors on the left side of the diagram, but from different ECM pins.
Electrical Diagrams — 2007 Chevrolet Suburban 4WD V8-5.3L Service Manual | Operation CHARM
Detailed repair manual for the 2007 Chevrolet Suburban 4WD V8-5.3L.charm.li