helidiesel
Full Access Member
Voltage drop the fuses is what the link posted is about. That will also show you where to start with the draw.
Incorrect... A good amp clamp (Like a Midtronics) will pick up a parasitic draw easily. 50mA is what's usually considered max for "normal draw" and an amp clamp will get you within 10-20mA of an inline meter at that range.
Put your hand on the alternator with the truck off. If it is hot replace it as it is drawing your batteries down. There is a test you can do with it running for that but I forget how to do it. It may charge "fine" while still having this problem though so keep that in mind...
If it's not the alternator drawing them down and you're sure you have a parasitic draw go into the fuse box and check for a voltage drop across fuse pins (The nubs on the back). If there is current flowing through the fuse there will be a slight voltage drop across it.
But before doing any of this test your batteries!