2002 ford excursion (diesel) won't start

[atvcrazy]

I have a 2002 ford excursion diesel 7.3L v8, replaced batteries 6 months ago, went out a week ago to start it. wouldn't start. Turned over a couple times then started clicking. Had the batteries tested, one was bad. Replaced both batteries again, Went out today to start it same thing. Sounded like the batteries were dying and then it just started clicking and the guages were jumping. Jump started it, when I shut it off it did the same thing. Any suggestions, My husband is away for work. I can't leave this truck sitting for three months.

[blewallen_gt]

Somthing electrical is staying on in your truck. A jump start won't charge your ne w battries. You must run it a good amount of time to charge them from your alternator in the truck, otherwise you must put the batteries on a charger (each one). Then you must find the power drain. Something like a light stuck on inside or a accessory pluged into a jack etc...

[ExUAW-AAP1995]

sounds like a bad altenator, running off the batteries until it runs out of juice. Jump it off then remove the positive battery cable, if it dies when you get the cable off then the altenator is bad, if not then you can start looking for a source of power drain.

[BroncoJoe19]

An alternate method of testing the alternator is to check the voltage across your batteries. It should read 12.66 volts without the engine running. Then once you get the engine started (whether with a jump or not) the reading should be about 14 volts. IF not, the alternator is not working properly, check the connections to the alternator, and the engine ground. IF all is well the alternator is bad.

[ExUAW-AAP1995]

yeah you can do that also but if you do not have a meter and looking for a stone age way for checking,LOL! Then do what joe says and check all connections.