Anyone in here really familiar with the BCM functionality and serial data wiring?

[EMX5636]

So quick backstory... I bought my 09 H3T last winter, and after owning it for a bit, noticed some backyard wiring fixes. Found a broken wire at one, so I removed their single wire (loomed at least) jumper that ran all the way around the engine bay. Noticed another one that I haven't been able to figure out yet. The engine is out of the truck, so I decided to dig into it today. It's ran from the PPL wire (pin 44) at the EBCM, into the cab to the PPL wire on the OBD2 port (pin 2). It's just wrapped around a small section of bare wire they trimmed, so they didn't cut anything. But if I removed it, I was getting a Service Trac Control error.

So, did some digging, and found two corroded terminals in the oval connector below the BCM. BRN/WHT and GRY. From what I can tell, one comes from the T/C switch on the dash. I tested the wire from the EBCM, and it definitely has continuity. Same with the wire from the BCM to the DLC/OBD2. What baffles me (unless I have a bad BCM) is why jumping those two purple wires keeps the code off (pin A41 and A38). I unfortunately can't test the fix until the V8 goes back in, and I get it finished, but it's the only thing I found after un-looming as much of the body harness I could get to between the two controllers.



Sorry for the novel, but trying to provide as much info as possible. Thanks!

Justin

 

[crwalkerasla]

Do you have the BCM wiring diagrams? I downloaded it from the forum and it helped me with some 'electrical anomalies' I was having.

 

[crwalkerasla]

Do you have the BCM wiring diagrams? I downloaded it from the forum and it helped me with some 'electrical anomalies' I was having.

 

[Jeepwalker]

There are a lot more guys on the Colorado forums if ya ever need really deep BCM and wiring info you aren't finding.

 

[EMX5636]

I do have the manuals from Schwarttzy that are helping. Problem is, I traced the wire, and it seems to have continuity, so I'm not sure if the jumper is covering up something else. I'll do a little research on the 355 board. Thanks!