2004 ford expedition battery drain?

I was having issues with my 2004 ford expedition starting because of a battery drain. We have replaced the alternator and battery but the issue continues. Now the radio(not factory) won't start either. I'm not sure how to trouble shoot a battery drain or have the tools to do it any other suggestions would be greatly appreciated.

If you have a new battery and new alternator and the battery is loosing it's charge after sitting overnight then you have a parasitic drain on the battery. Can be any light that is on. Curtorsey, brake, trunk, under hood, glove box, any light. Can also be a relay that is stuck.

First thing to do is the unhook the battery ground cable clamp one night when you're done driving. Next day, hook it back up & see if it starts easily. That will tell you that battery is good. Then, there's a larger fuse box on the driver's wheel well under the hood. Make a leak tester, a car light bulb with short leads soldiered to it. Pull the fuses one at a time in that box & check the circuit where the fuse should be with the blub tester. IF onj of the fuse sockets lights-up the bulb when you test it, there's your faulty circuit. Then you keep digging in that circuit, using the tester, until you find the drain.