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Cat 3126 Ecm Wiring Diagrams Caterpillar Ecm
What are peaople saying https://www.thetruckersreport.com/truckingindustryforum/threads/3406e-bad-ecm.729483/
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ECMs are pretty tough. Problems like yours are wiring related 99.99% of the time. Another test you can do is to load test those power and ground wires. With the OEM connector disconnected at the ECM, jump power one at a time from pin 4 and 6, through a headlight bulb, then ground the headlight to make it come it on. If the wires are in good shape, that headlight will be nice and bright. If the wiring is weak with a bad spot, the headlight will be dim. Your volt meter cannot load test the wire, so a bad connection will still show full battery voltage. That bad connection cannot support an electrical load, that is why you get weird ECM problems like this. While the head light is connected wiggle your wiring harness all the way back to the either the batteries or the starter depending on where it gets its power from. If the wiring has a bad spot, the headlight will flicker or drop out. Repeat this for the ground too but reversed. For sure, any corrosion needs to be cleaned up or replace those pins. Also, it is best to have the proper test pins, that way you can see if any pins inside the connector body are spread and making poor contact. I would also try a test ECM for a few days if you can before spending any money on a new one.
UPDATE: So, unfortunately heavyd was right… I have a break in a wire somewhere between the fuse box and ecm on the constant power side. Here’ my current problem. I can’ f8nd a schematic from international for a 97 9300 w cat motor. Or any motor for that matter… I unbolted the fuse panel to see what color the words are coming from the ECM power reed breaker. The wire appears to be tan at the breaker but when I test the wires coming through the firewall I can’ figure out which wire it is because none of the tan wires has voltage without the key on. I can’ get the fuse panel out enough to really trace that wire without taking the dash out and I can’ find a schematic online. I’ stuck again. Can anyone tell me where I can get a schematic for a 97 9300?
