Possible BCM issue?

[uzurhead]

Recently purchased a 2018 3500 HD and on the way home a service trailer brakes message came on along with ABS light. There was no trailer being towed. It eventually went away as the drive continued.  After arriving home I plugged in my horse trailer to check everything and the left trailer blinker would not work and then I received messages of service trailer brakes and check trailer connection. 

No issues with this trailer and my 2012 3500. 

I checked fuses and saw that the 12-volt auxiliary was missing a fuse and corrected that. I ohmed out all of the other fuses associated with a trailer.  I disconnected the connection at the rear of the truck that supplies signal to the bumper and in bed outlets. I got a very weak voltage reading on the left blinker so the issue stems from that point forward.  With random messages and funny acting lights, I have read in numerous forums that it's the BCM. Can anyone please advise?

[silveradosid]

i would buy a scanner that can clear the codes first. the bcm seem to save resistive settings of the  lights 

clearing codes even if there isn't any seems to reset the system

[uzurhead]

10-4.  I'll do that before testing that wire periodically down the truck.

[asilverblazer]

I would suspect any number of wiring faults before a bad BCM.

[uzurhead]

Got it scanned and a code for RR wheel sensor appeared.  A mechanic said that it alone could cause the symptoms I have mentioned.

[asilverblazer]

A wheel speed sensor causes lighting issues? I doubt it, the service trailer brakes and ABS light, sure.

 

On 5/13/2024 at 5:24 PM, uzurhead said:

service trailer brakes message came on along with ABS light... I plugged in my horse trailer to check everything and the left trailer blinker would not work and then I received messages of service trailer brakes and check trailer connection...

I got a very weak voltage reading on the left blinker so the issue stems from that point forward.  With random messages and funny acting lights...