2000 Express Battery Drain

I have a 2000 Chevy Express with a Regency conversion, if it's not started in 3-4 days the battery dies. Something is slowly draining the battery. When the battery is disconnected and reconnected the Function Actuation Module makes a clicking noise....is this normal? Could this be the source of the power draw? Any help appreciated. Thanks!

I have a 2000 Chevy Express with a Regency conversion, if it's not started in 3-4 days the battery dies. Something is slowly draining the battery. When the battery is disconnected and reconnected the Function Actuation Module makes a clicking noise....is this normal? Could this be the source of the power draw? Any help appreciated. Thanks!

First make sure the battery is not old and weak.

Try a battery disconnect and see if battery goes dead disconnected.

If not you will need to run a amp draw test on electrical system to find the draw.