Losing engine gauges, speedo, and fan staying on

[Mrkentee]

(05-24-2025 )Colter Wrote:  It should be communication issue between ECM and CAB. Low voltage at the power pin in the 9PIN or the J1939 voltage?
If you have ESA you can connect to CECU and check for any code listing a CAN line failure. These issues are usually outside the cab under the hood, I would start by finding the blue resistor plug in the OEM harness along the drivers side of the valve cover. It'll have blue/yellow wire pair in and out of it. There may be a loose pin or a rub somewhere in that wiring.
Peterbilt also tend to get rubs in the ECM power supply but the symptoms don't really match that, I'd assume your hours and KM go to dash's when the issue happens as well?

Low volts at the J 1939 connector on the lower left will you connect your diagnostic equipment. Yes mileage and hours go to dashes, as well as elog can’t tell anything. I don’t see any problems with the wiring in the front, but I haven’t ripped the whole thing apart. I did look at that Resistor and it looks OK. Right now it’s working for about the last 40 minutes except in for a couple minutes. I guess if it is a wire problem, I’m just gonna have to dig it and try and find it.
No, I don’t have ESA. I only have an in-line five, and insight. I have calt$rm, but I don’t know how to use it unfortunately. I really need to learn.