Ecm power supply issue.

Hey guys.
I just happened to notice your need for ECM power supply help.
I'm trying to confirm ground and positive power from what I believe is 3 seperate sources to the ECM . One thing I can't discover is the exact location of 2 of the 3 sources. One connects to batteries, the 2nd I'm told is at ignition, but is it right at the ignition switch or a relay which turns on via the ignition switch .
And the 3rd I'm at a loss to find.
It's a 2003 CAT 6NZ/C-15.
Stumbling / power reduction one minute ( or an entire day...week ) and all good the next, lasting the same, an hour, a day or more / less.
Weird is, after 11 hours truck running, it all calms down and runs 95% great.
Help !! Is all I can say.
10's of thousands of $ I've spent trying to rectify the problem still not there.
Any help is appreciated .
Regards;
Text me if you're short on time.
905 746 5505
Thanks again.

 

Not a good idea to put your number on a public forum. Your choice though.

Also, the gurus on here might benefit from knowing if there are any codes being thrown.

 

pin 48,52,53 are un switched battery positive. (many truck manufacturers only use 2 of these wires) most trucks run these direct from battery box with the fuse next to the battery
pin 63,65, 67 are un switched battery earth. (again many truck manufacturers only use 2 of these) these can be to chassis, to engine or to battery depending on truck manufacturer
pin 70 is switched positive from the key/ignition.

 

Sorry for delayed reply, taking care of dad with medical issues these past weeks.
Anyhow. The reference you make to
"Pin 70 unswitched positive from the
Key/ignition in your last reply. Is that a connection directly at the ignition switch, or some sort of relay that powers itself as a result of the key being turned ?
Also ( seeing as we are on the topic) behind the dash panel behind the steering column, there's 3 black cube like power blocks, which 2 are identical to each other/ side by side, and the 3rd being a few inches deeper back and , guessing, is about 3" X 3 " square with heavy guage power wires to it. All 3 are firmly screwed down.
Are any if these 3 black cubes in any way related to ECM powering or a engine management system of any kind?
Trying to isolate my problem and either rule in / out a electrical problem with my 2003 Peterbilt 379 with 6NZ CAT ,18 speed..
Thanks for your help.
It's VERY much appreciated.