Cat CB64 electrical problem

[Vetech63]

Serial # DJM00485

The battery is being drained of power when the master switch is left on. I do have a electrical schematic and have been trying to trace down the problem and I believe I have narrowed it down to a particular circuit, but I'm not positive yet. I disconnected the switch side of the ground cables from the master switch leaving the battery side connected. I have system voltage at every ground location but no amps so nothing is burning. I have taken a pic of a particular part of the schematic.....

If you can blow this up a bit, you will see the ECM circuit breaker on the right side of the page at square G12. If I remove the distribution side of the circuit breaker that feeds the battery power to the ECM my voltage drain stops and drops to .03.
I have checked the alternator and the starter motor and have found no issue with those.

My question for product support was going to be........is it possible for a small ground short inside the ECM that would not effect its operation and display no faults? Also......could it be possible for the switched ignition for the ECM to stay on even though the machine shuts down and has no display?

The ECM is stuck behind the engine against the firewall with almost no access or some of these questions I could answer myself. As you can see, it will take one of the Olympian Midget Contortionists with 5 foot long arms and eyes in their fingers to get to it.

No other circuit have I found that will kill the power draw other than this ECM circuit. Any suggestions, or experiences with this type of thing?

Yeah...........

........NO ACCESS AT ALL.

 

[heymccall]

Does it have Cat's Product Link? Product Link on my Cat 328D machines (all three) will kill the batteries over the weekend.

Simplified schematic.

 

[Vetech63]

Thanks for the simplified schematic.....that will save alot of eye strain for me! I'm not sure about it having a product link, but I will look at that today. I'm not extremely familiar with that feature.

 

[Nige]

I'm not sure about it having a product link, but I will look at that today. I'm not extremely familiar with that feature.

According to SIS it wasn't equipped with PL when it left the factory. It could have always been added afterwards though.

Look for electronic controls in the locations shown in the two diagrams below. These are the two possible options of PL control arrangements that could have been installed.

 

[Vetech63]

Sorry guys, I'm just now getting back to this. I did find the product link.....evidently added sometime after manufacture.

After looking at the electrical schematic, the operator's manual, and the fuse lid decal........I noticed something didn't match up.



The lid decal was the correct orientation, the operator's manual was not. After some cross referencing between the 2 I found the 7.5 PL fuse and pulled it which corrected part of my electrical draw. (Thank You Mr. Mccall!)

 

[Vetech63]

The rest of my current draw is from the machine ECM location @ A2 on the black panel. Do you know if there is an allowable current draw and what that might be? I love these tight areas........

 

[Vetech63]

According to SIS it wasn't equipped with PL when it left the factory. It could have always been added afterwards though.

Look for electronic controls in the locations shown in the two diagrams below. These are the two possible options of PL control arrangements that could have been installed.

View attachment 248961View attachment 248963

And a Thank You to Nige. Without your input on the PL I could have spent hours removing panels trying to locate something I was unfamiliar with. Your post was dead on also!