Why would my lincoln navigator drain my batery

A Lincoln Navigator is not a JEEP.

DRAIN THE AIR FROM SYSTEM COMPLETELY AND THEN TURN THE SHUTOFF SWITCH BACK ON

check your alternator

battery draining at rest. check for drain turn off all accessories. disconnect ground. attach a testlight in the bridge between battery and ground cable. if the test light glows start removing fuses one at a time until the light goes off. replace each fuse that doesnt quelch light immediately. when you quelch the light you have a circuit to inspect thsat is draining the battery

Drop Headliner & check for a drain hose being off

Lossen the head liner & see if the drain hose is off the
sun roof

mine had a broken arm and that caused my battery to drain check that

more than likely you have a wire grounding out somewhere. could be loose terminal or if you have lead terminals the smallest crack in them will drain the battery.

IF YOU MEAN THE DRAIN FOR THE HEATER BOX.
LOW ON FIRE WALL RIGHT OF THE ENGINE .