Between Omaha and Des Moines, 7 miles South of I80 | Pofarmer - 1/20/2017 21:06 Cummins N-14 ECM 3 wire lead is direct to batteries. The thing still turns on with the key, so I'm assuming a voltage problem somewhere. Occasionally, when I've say, turned the fan on high, it will kill it. When I started the wipers yesterday the engine warning buzzer went off for a second. When it "cuts out" it dies, goes to zero RPM's. Generally no stumbling. I haven't worked on any Cummins, before, but found this schematic on internet:(mentioned it was for a 1995 engine) 
They mentioned that pin 26, was the keyswitch wire (if that is true) . I would do voltage tests, on all those pins(grds, 12 volt, and keyswitch) at that 28 pin connectors, and you would have to add some resistance to, while testing (measuring voltage) to see if you have a big voltage drop. Not sure if a small test lamp, would be enough = I used a 12 volt DC spotlight, that I knew drew 5 amps, when testing these types of wires, going to a CAT ECM. Note: Just testing at that 3 pin connector isn't going to be "good enough" 2nd note: May need to operate some extra cab accessories and wiggle keyswitch and wiggle wiring and wire looms, while testing also.(during each voltage measurement) I feel, step 1; is to prove the engine's ECM is getting all the correct voltages(while pulling some amps, thru the wiring) so you can "Divide and Conquer" and move towards the problem area. Heck, even looking at that little schematic, and you mentioned the 3 pin connector is going directly to batteries, that still leaves "possible poor connections" from 3 pin plastic connector over to 28 pin connector and/or corrosion in 28 pin connector, besides all the "cab electrical connections" that feeds the keyswitch, then returns back to that 28 pin connection. |
1993 Freightliner FLD112 electrical problem
