I am having issues with my 1997 B2500 Van with 5.2 that I cannot seem to figure out what's happening. Starting first thing the van runs fine, I show the voltage is good and no problems but once the van has ran for a while (100 miles of travel or more) it stops charging the battery and eventually lose all charge. I slowely start seeing the voltage drop late in the trip (unfortunately when I'm away from home) and if I'm lucky and it's not getting dark I can make it back otherwise the headlights will kill it quickly and I end up stranded. I replaced the alternator but still seeing the exact same behavior with the new one. Any help would be greatly appreciated. It's my only vehicle so I can't afford to have this keep happening but also unemployed so cannot afford to have a professional repair.

 

Something to check that is free you can do. Pull the high amp fuse in the fuse box under the hood for the alternator and inspect the connection. Take voltage readings on both sides of the legs with the vehicle running. Check wiring closely where wires connect to alternator. I see on the net some guys are adding an external voltage regulator, matching the system of an earlier Chrysler design. Just my suggestions not being a certified tech.

 

If you stop long enough for the engine bay to cool down does it start charging again? If you do stop for a bit to try this, pop the hood or spray some cool water on the ECM to help it cool down faster. The ECM regulates the alternator voltage, so if it's overheating that might be why the charge is failing.

 

Do the vans have the battery temp sensor as well? That might also cause the PCM to kill the alternator.