Ford has what is called a Battery Saver Relay, in 2001 it is in the AUX Relay Box 1, small black box above gas pedal area I believe, interior light relay is in the same box.
It is suppose to disconnect power from cab circuits after 20-30 minutes of vehicle being off.
So battery won't be drained if you leave something on.
See if you can feel that box "clicking", the source of the noise.
It wouldn't be related to wipers.
GEM(generic electrical module) is behind the radio, it controls most interior electrics, including dome lights and wipers, but it is a sold state device, no "clicking" relays inside, BUT(big but) it does control alot of relays.
Last edited by RonD; 01-27-2016 at 09:57 PM.