Recently purchased a Dodge 03 ram 2500 Cummings turbo. OBDII port was kicked off, getting the wiring diagram from dodge Mon. Purchased the vehicle without the secondary battery, put a new one in and it overcharged lost all voltage. Cleaned the battery connections put a new battery in on the drivers side it starts up fine but loses voltage and check gauges light comes on when it idles up to 1000 rpm and runs completely off of the alternator. Figure it is grounding issue with the data connect/OBDII port so I taped and secure with electrical tape. Still having the same issue, am I missing something, or overlooked something? I have good mechanical experience, just rebuilt the heads on my fathers 98 Lincoln town car signature series, with dual ovh cams. I have done numerous other projects as well but this is my first diesel and really love the performance of the truck. Any help would be greatly appreciated. Thanks and I think this forum is great!

 

Ok here is what I have come to gather regarding my electrical issues. Fixed the data connector/obdII port, so now I can read errors, but what I going to do instead of clearing the codes is reset the PCM by disconnecting 1 battery completely and only the negative battery on the other and turning it to full crank for 30 secs. Some guys touch the neg cable to the pos side to drain the capacitors within all the electrical by I will use the crank method first. It should dump everything, shouldn't have any error codes and can began diagnostics from there if it does not fix the problem.

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Wookin Penub in all the wrong places, first place I need to start is the alternator wire to the negative battery terminal on the passenger side battery it has completely corroded off. It mounts to the back side of the alternator so I will check to see if it was wired correctly, found out ground wires are 1/0 and positive wires are 2/0 good thing I work for Dakota Supply Group we sell wire in bulk reels.

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side not obdII scanner would not read my data port so I had to do a BCM test by pushing in the odometer and turning the key to acc in order to get a code read. Will continue to work out the bugs.

 

i am looking closely on the posts to reach on an apt outcome .. now the time juggling the the ideas as getting very few to rest on a desired selection

 

Ok, fixed the corroded wire from the alternator to the positive passenger side battery cable, I have an equalized charge between both batterys but I am still getting code read errors, courtesy/dome output circuit shorted or open, cargo lamp output circuit shorted or open, as well as battery voltage open. Ordered a auto range muiltimeter from our company and will go through the electrical. I have decided to build a completely new battery harness for my vehicle, seen a lot of green corrosion and brittleness in the cable wire going to the backside of the alternator. Problems are not critical just have to do a little tlc. Also I have decided to put in a Kats recirc heater for the tough winters in the Midwest. Should be good to go by late next month.

 

Sounds like it could possibly be a bad BCM, and BTW it's a CUMMINS