over 3-4 weeks the Battery drain down, I think car is supposed to have an electronic disconnect to pre vent this?
I don’t know where this comes from but no it does not. Explain what is the reason for battery problem. Setting undriven for some time , just losing its charge over 3 or 4 weeks . Have you had the charging system checked ?
If it has the original battery then maybe that’s the issue.
Both of my Lincolns and my son’s Lincoln(s) have a high current draw when first shut off. It takes 45 minutes or so for everything to go to sleep and lower the draw.
A weak battery may not take this high current draw and especially when combined with 3-4 weeks of sitting.
Test the battery and check for the parasitic current draw which should be in Milliamperes; both when first shut off and when the electronics go to sleep.
I’m sure it does go into a sleep mode to reduce current draw within an hour of parking it. Even so, 4 weeks is a lot to expect for a battery. The battery on any car would have to be in pretty good shape to not drain down in 4 weeks to a pretty low charge state. The current draw in the off state can be easily measured , has that been done? The other things that can run down the battery are lights being on (like the trunk light, glove compartment light etc) and faulty door switches causing the computer to think people are getting into and out of the car, which turns on the computer each time.