2011 Electrical fault gremlins

[Midland]

More random thoughts. Make absolutely certain you have good voltage into the BCM. Big red wire that comes through the firewall and bolts into the top of the BCM. That wire comes from a battery source which is under your air cleaner and hidden by a red rubber cover about the size of a deck of cards. The fact you have this problem almost immediately when it rains certainly makes me suspicious of that area. Do the testing with a good DVOM and not a test light as you want to know if there are voltage drops and if so how much they are. It is interesting to me that you have all the engine data showing on your dash but no chassis information. As I had mine torn apart it became increasingly confusing how the data link(s) work with and apart from each other. Maybe someone else will elaborate on this, but it appeared to me that I had separate drivetrain, chassis, and radio J1939 data links but then they were still all tied together in a black bock about half the size of a pack of cigarettes, off at the right upper side of the instrument cluster (behind it, you can't see it until you pull the IC). Obviously I don't fully understand all the intricacies of how it all works together, but it is interesting that you have your drivetrain data but not your chassis data. I ended up purchasing Diamond Logic Builder from my dealer (with next day air) only to discover you can purchase it more or less instantly online. All I got through the dealer was a postcard with a key-code. You download the program online either way. $600 the first year, cheaper for consecutive, and you still need a Nexiq or Inline to plug into the network. However, International has all their own code system for the chassis and these codes don't show up on your dash (at least not on mine). So, I had codes for problems I observed and had repaired from pre-trips and observation, such as "left headlamp low voltage" (yep, the headlight was out), "actuator not working" (yep, no floor heat), etc. You can also view a page with the IC and via the software turn dome lights on and off, run gauges up and down, run the turn signals, etc. from your laptop. It will find your VIN and knows each option your truck has and will determine (at least by my observation) if each and every system is being seen by the network and/or functioning as intended. For me it was worth the money as I would have had to have my truck towed to the dealer (and then back) to get this information. You can probably get your dealer to read and print it for you for $100 or so, I've never had mine to the dealer. Diamond Logic also shows all the BCM plugs and where each wire is supposed to go or what it is supposed to feed. The other thing (really frustrating) that I discovered, and which was just discussed in another thread (about how the ambient temp sensor can shut down the AC system) is that things are tied together and dependent on each other that would make no sense to you or me, at least until we are aware of it. In other words, if you know of (or the Diamond Logic report shows) ANY components that are not reading or functioning properly, FIX THOSE FIRST! And keep all the components and fuses installed at all times as you trouble shoot. As mentioned earlier, I unknowingly blew one of the mega fuses (under the red cap under the air cleaner) when I took the dash out or something (be smarter than me and unhook your batteries first) which one day caused the horn to blow continuously and the next day made the wind shield wipers run constantly when battery voltage was applied to the BCM. Dealer was telling me to by a new BCM. It was only a fuse, and one that is not tied to the BCM nor does it seem to have any real impact on the BCM, but guess what. It affected various outputs from the BCM. Don't shove voltmeter probes into plugs as you will likely damage them, and take a few breaks. I just spent over a week working on similar stuff, it will make your head spin. Please keep us updated.