batteries completly dead. troubleshot it down to glow plug circuit i think. in the fuse box under hood i would pull heavy gauge red wire off stud[just after 175 amp fuse] and voltage would hold. put wire back on after charging battery and battery completly drains [with truck off]. discovered with meter, with wire off, 0 ohms to ground, dead short. worked throught the circuit a little more and i have the short isolated down to the wire that feeds the glow plug "common buss bar" i guess you would call it. i guess where i need assurance is with the resistance reading im getting to the glow plugs. should have some kind of resistance to griund right? anyone know the ohms value for an individual plug? my guess is that i just have shorted gp. for now, ive just taken the red feed wire off the stud there in the fuse box under the hood and the batteries stay charged and everthing else seems to be working fine. i hope i made sense. here is the print i have been using for refrence page d-102. http://www.gmupfitter.com/publicat/2004_BB/2003_Beyond_LD_Electric_CK.pdf