7.3 No Start

[sgg93]

I've been chasing an electrical gremlin for several weeks now, as I was having a problem getting the driver side battery to charge. On a hunch, I decided to change the battery cables, as I suspected there was some internal corrosion. I changed the positive cable with the one from NAPA, and then changed the negative cable on the driver battery, also with one from NAPA. On the driver battery, however, (the most suspect looking cable of the bunch) the folks at NAPA had provided me with the wrong cable, so after taking it loose, I realized the problem, and simply re-installed the existing cable. After doing this, I was faced with a no start. I have a wait to start light, and the tach shows RPMs when cranking. I then put both batteries on the charger and got them to full charge. I attempted to start the truck again, and was confronted with a no-start. The check engine light shows when cranking, and I have oil pressure when cranking. I still have a wait to start light. This is exactly how the truck behaves with one dead battery, but since both batteries were fully charged, I knew this wasn't the case. After 3 attempts to start the truck (maybe 5 seconds each), there wasn't enough power to turn the starter over. I noticed the ground cable on the driver battery was warm, but the one on the passenger battery was not. I deduced that there was a problem when the driver battery was almost dead when I put it back on the charger. I checked the HPOP reservoir, and it was within an inch of the top. I also checked both of my ground connections on the block and cleaned them. With this in mind, I'm tempted to believe the alternator is faulty (which is what has been causing my battery issues), and that this over a long period has degraded my driver battery. Static voltage on the terminals of the passenger battery was 12.4, and the voltage when cranking is 10.3. I'm going to load test the batteries tomorrow, in hopes that I find the driver battery faulty. I still suspect the alternator as being the root of my problems, but wonder what's causing the no start.

Any ideas?

sgg