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hello i have a case study with this cummins its not charging the system
the owner had the engine rebuild since the engine rebuild was made know the system is not charging
batteries should be at 13.5 or 14 volts but its not reaching the gage mark from the dash board it at 12.2v
it has a new alternator (i didnt replaced the alternator owner did)
checked battery cables and everything is good nothing loose
alternator harness connector has a good ground but ecm control signal has no reading. i did a resistance test on the harness across the terminal connector engine on and it was not on spec according to all data, but when i disconnect the ecm terminals the resistance goes away
i checked ecm power and ground feeds and everything is ok my next step is ecm that is bad any suggestions i would gladly appreciate
Hi Eduardo, can you be specific about the readings on the tests you performed?" No reading" could be interpreted as open circuit. I would check wiring integrity before replacing the ECM. Pig tail connector problems are common on these Dodge trucks. You can test the alternator by momentarily supplying 12 volts to the alternator on the Field Control side of the alternator connector; The alternator should charge over 14+volts. Again, wiring integrity check would be my main focus before replacing the ECM. Keep us posted and thanks for sharing.
hello i checked the control side and ground wire for resistance i tested ohms on bothe wires and there was infinity no resistance and these are the tests i did
1; continuity on bothe wires and there was good continuity
2; short to ground test: connector to alternator disconnected the ecm connector disconnected,, I placed one test lead on one end of the wire and the other test lead on a good ground and had no resistance( i had the resistance on my dvom at the highest reading )
3; checked alternator connector and it looked good and i also checked the ecm connector and it was good too
4; battery cables. i cleaned and inspected the positive cable and the negative cable everything looked good
5 i put the test lead to the alternator wire that connects to the battery and the
other test lead on the battery positive (auxiliary battery) the dvom was on volts and my reading was 0volts
thank you for your help and time!! i am going to do the test you told me right know i will let you know if the alternator is no charging with this test thank you again.
You should have a short to ground on the ground side of the connector. There should not be infinity reading on this wire. Looking at the wiring diagram one pin is connected to ground G120, the other goes to the ECM and is the one that controls the on time for the alternator.
you are right that was the problem when i was rechecking the ground i saw that i had voltage on the ground side wire know i am going to put everithing together and have that truck on the road!! Ohmega diagnostics thank you for your help!!
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