I have a 2005 PSD that for the past few months has been giving me trouble starting and the dealer could not figure it out (tested alternator/batteries). Here is some info (not very mechanically inclined so excuse some bad terminology):

-after sitting for a few days the batteries won't have enough juice to crank
-if i try to crank the speedo/rpm needs will trickle a little
-hook it up to a trickle charger to let it charge and everything works fine. Charger will read one of the batteries to be almost dead

perhaps the cabling between the Alt/batteries is bad? or something is drawing power?

any ideas?

 

Are they original batteries from 05? If they are...I would say its time for a change...

All your symptoms are looking like bad/low batts when you crank it up.

Check all cables/grounds and give em a good cleaning.

Test and verify alt output