GM-GMC: 1998 6.5TD 1500, mcmaster carr supply, stainless steel studs

Question
i had a similar electrical problem that Bob had asked on November 29, 2005. the differences are the passenger side battery yields 12.5 volts cold and the drivers side is 11.8Volts. For some reason though there is not enough amporage to turn over in these winter months. i've rebuilt the starter, changed the alternator and put two new batteries in to no avail. still no juice to turn over and when it was running before the intermittent non-starting problem arised the charging would go up and down between 9 and 13.5 volts. basically it would charge 'sometimes'. i'm in the midst of getting the electrical diagrams from my local dealer but was wondering if you've ever run into this before so i may have a quicker route to find this ghost and excercise it. please help. thanks for your time.

ed

Answer
Edwin,

The battery cable connections on the GM diesels suck.  I would very carefully check all cables for corrosion and proper contact.  Clean every end up, including the ground cables.

Your charging system should show about 14.5 Volts at idle.  Your batteries may be weak and, if they will not charge properly, they both should be replaced.

I replaced the cables on my diesels with 1/0 welding cable.  At the batteries, I installed short stainless steel studs, stainless steel washers, and stainless steel self-locking nuts.  You can buy the hardware from McMaster-Carr Supply and the cable and cable terminal ends from a welding supply store.