The battery drains down in 48 hrs. I had a Ford mechanic look at it but he could not find out why it happens to my 1997 lincoln town car. Jim

I will try to help. First, find out if the Cruise Control was recalled for your car. Have a dealer run the Vin#. The bad ones never shut the power off.

Next, rear window defrost switches can short without the light indicator being lit up. This is a hard one to diagnose because it cycles every startup. Also bad ignition switches can leave the ignition on. Its silent and is not visible.

If none of the above, you have 2 ways to test the car.
Use OHMS or VOLTS. With volts you put the meter between 1 battery cable and the battery. You can short out something with this method. I favor the OHMS method, which you disconnect both battery cables and put the meter on the cables.

You will have to pull fuses with either method. Its time consuming but once you write down the fuse placement and size you will eventually disconnect the grounded fuse. Then trace the system, like a bad window switch or trunk pulldown.