03/29/2026
2000 Dodge Ram R2500 5.9L
Electrical Diagnosis!
Customer States: My engine won't start and my power distribution center is making a loud buzzing noise when the key is in the on position. Please inspect and report.
Technician completed a preliminary diagnosis and found the ASD relay not being properly pulled to ground by the PCM. Technician noted approximately 8V present on the ground wire for the ASD relay with the key in the ON position. Technician disconnected the PCM connector C3 and tested for continuity between terminal 3 at connector C3 and terminal 85 at the ASD relay in the PDC. - 0.1ohms present. Technician load tested the wire and noted the wire passed a
load test. Technician moved on from here to testing PCM powers and grounds. Technician noted PCM grounds OK at close to 0.1v, but noted the PCM fused B+ was only at around
8v with key in the ON position. Technician tested for continuity from the output side of fuse 3 (20A) to the PCM and noted 0.1ohms present. Technician load tested this wire and noted the wire passed a load test.
Technician reinstalled fuse 2 (20A) and PDC to vehicle and noted when wiggling wires beneath the PDC the PCM would intermittently receive source voltage and then would ground
the ASD relay. Upon further inspection the technician was able to isolate this fault to a broken/burnt/melted 20A fuse that was still making connection (not completely burnt through) but was not making a well enough connection to provide proper voltage to the PCM. Technician found this 20A fuse to be the source of the customers concern after extensive electrical
testing taking place. Technician installed a new 20A fuse and noted the vehicle's electrical system is now operating as designed again after repairs.
