I am trying to trouble shoot a mysterious current draw. The truck is a 89 F250 7.3. It appears not to be charging properly as the voltage is around 13.6 -13.9 consistently, When the truck sits for a week the batterys are both dead. How should I tell if there is a current draw and where to test.

Thanks
Ken

 

place an amp meter into the line of any item you wish to check. However if it was me I would pull the alternater and have it checked for a bad diode pack.

 

to get a real basic charge test, you don't even have to remove the alternator. they can test the whole system in less than 5 minutes by just hooking up the diagnostic machien to one of the batteries.

now, if that shows bad, you'd need to pull the alternator to isolate the cause.

Mike