[408F150]

For quite some time I've noticed that anytime I leave my truck parked for 5 or 6 days the battery is almost always dead or near dead, and I recently decided to go probing around with my multimeter to see what was killing the battery. For a long time I didn't have my seperate work vehicle so the truck never sat long enough for this to happen.

After testing all my fuses and accessories I was able to determine that the Gryphon display unit is drawing 3.9 volts while the vehicle is completely "at rest" (takes a while for the ECU and all the peripherals to shut down after you turn the truck off). What could be causing this issue, and is this normal? Thanks for your help.