Baterry keeps draining

https://shoptoolreviews.com/automotive/diagnostic-testing/parasitic-battery-drain/34587/

You need to have a shop do a baterry voltage drop test on each fused circuit to isolate the cicuit and then to the component causing the drain.

A mechanic would disconnect the battery and check each circuit for a voltage drain by disconnecting the fuses and breakers. Anything with a relay or way to use electricity such as a light bulb or switch can cause a small short to ground or voltage drain.

chec vehicle for any lites on or noises from mechanisms--cud hav flaws in wiring harness--a normal alternator may hav a bad diode causin drain--disconnec main wire in rear overnite- then test batt--also voltage drop test can be done on fuse box to pinpoint a drain--details online

there is an open cirket somwhere draining the battery

Find the battery drain. Disconnect negative cable from battery. Place test light between pattery negative post and disconnected negative cable. If light is bright while no accessories are on, there is a drain. While keeping the test light in this configuration, pull each fuse out and replace on at a time while watching test light. If the light dims or goes out when a particular fuse is out, that identifies which circuit has the drain. Use that information to track down what is on or draining.

to truly eliminate the alternator you have to disconnect from the wires over night to see if battery is still drained good chance that alternator is the cause.you also can put a test light in between the battery and the ground cable (negative)as you disconnect the alternator you should see a difference in the test light. the bulb will dim down if alternator is draining the power.

the brake lights switch of the expedition is connected to the cruise control system. get yourself a wiring diagram and sort out the problem. i have read of fires being caused by that problem so be carefull.

This might be a switch  - test the switches. You can pull the fuse if you are driving during the day to save disconnecting the battery.

This gona sound ignorant and obvious but you have a short in the abs sys or ECM -----get a code reader from Advance auto to see if you can pinpoint the issue----you give them a deposit then when you return code reader they refund your deposit---oh have you changed anything in the vehicle such as radio----added speakers---had an accident--new ign sys etc etc---GL