Ford Repair: parasitic battery drain, volt drop, diode test

Question
Tim, I have a short in my 91 Ford Explorer 2WD.  It will drain my battery enough so that the vehicle won't start after about 4 to 8 hours.  I have placed my meter between the positive terminal cable and the positive battery post with nothing running and was drawing about .599 amps.  I removed every fuse in the vehicle and in the engine compartment one by one but the current was still the same.  Do you have any suggestions as to where to look from here?

Thanks for your time,
Rich

Answer
Richard,

Good Job on your parasitic battery drain test. It is not often I get to hear from someone knowledgeable.  I think the only thing left to test is your alternator. A bad alternator diode will cause a parasitic battery drain also.  Disconnect the positive post from the alternator and use a DMM on the diode test function. You should have a .7 volt drop between the post and ground in one direction only. When you swap the meter leads around it should read nothing.

I hope that is of some help.