OK guys, I realize I may not have the whole story here, but maybe someone who has seen this setup can point something out to me. Something is definitely off-track here. Probably something simple, but I'm blind to it today. Here's a snap of the cluster for reference. Sorry I don't have more, but it was a hectic day. Here's the situation. When we got the truck in the shop, none of these gauges worked at all. I didn't have time to look at it quickly enough so we sent it to a trusted supplier/service company to have a look. A few days later they called and said they had achieved some success; the top row of 4 was alive and working fine. However, the other rows (7 gauges) were not, and they were stuck, so we got it back. So in I go to see just what's behind all of this. I find that all of these gauges are on a common bus, well possibly 2, and use just short 4 wire jumpers between them. The far left upper gauge is fed data and power over 4 wires that simply plug in to the back. An identical plug allows that jumper to hop to the next gauge. And so on. So far, so good....for the top row. Now for the puzzle. The other 7 are set up the same way, with short 4 wire jumpers connecting each gauge in the string. HOWEVER, on this group, there is no wiring inbound to supply data or power. They are all just jumpered to each other on a loop. So of course they do absolutely nothing. I've had the dash scattered about as far as I care to, but cannot find a stray wire that might feed this gauge group. And to make it more interesting, there are no empty sockets on these gauges, so nowhere to plug it in if I were to locate it. I have to mention though, that on the top row, the last in the string, the brake pressure, if memory serves, does have an empty socket. Seems there should be a terminating resistor or dummy load of some kind. Something tells me I am missing some wiring, or perhaps one of the larger connectors lurking in the dash that is connected to nothing perhaps has an adapter cable to bring 4 wires out for the lower gauge set. I'm without any diagram or schematic on this thing, and the shop that we had try it had access to Mitchel's but told me it was no help. They are pretty good, so I believe them. I have no contacts at the dealer and usually sot of get the cold shoulder when I go there. That's fine, I don't usually get much truck work. If anyone can offer any hints or guidance, I'm all ears! Anyone familiar with this setup?
Sort of need the PACCAR ESA software to get very far with that issue. And a wiring diagram. And make sure your alternator isn’t leaking any A/C into the can bus. A leaking diode will cause weird problems like that.
Coaldust, my main concern first it simply getting the gauges reconnected. Like I said, the group of 7 is not connected to anything but itself...that's where I need a schematic. I suppose it's possible that ALL 11 of the gauges could be in series, but if that's the case, I'm missing a jumper or termination for sure.
What’s the chassis #? I might have information around my mess of a desk on it. I’ll take a look.
Here is a link to the service manual. https://www.ametekvis.com/-/media/ametekvis/download/technical-support/peterbilt_387.pdf?la=en
VIN is 1NP-ALUEX-3-6N644282 That would be great if you did have something.
OK, that was a great read and explains a lot that I suspected. But I am not sure this truck has the 387 system, primarily because of the consistent reference in that doc to a 5 wire private bus line. The gauges I have are all on a 4 wire bus. Basically, I believe it is the same basic system, but perhaps a different Rev level or slightly different version. The layout is very similar.
That was just a guess. Let see, I can only pull up certain chassis numbers. Don’t see anything close. Ok. Try the 2005 body builder guide. Good wiring diagrams for the instrumentation. Here is the link. https://www.peterbilt.com/download/file/6081
This being a dumper, I suppose that makes it a 367. That guide is helpful, although mine is a '05 and that manual is a 2015. I would imagine a few changes would take place over 10 years.
Oops. I’ll try and find the guide for 2005.
OK, great! Much appreciated. I'll be out of pocket most of the day, so certainly no hurry. I'll check back in a little later.
Well, a measure of success. Went to consult with a couple of service guys at the dealer about how this works. All 11 gauges are on a single bus and should be connected head to toe with the 4 wire jumpers. I had considered that, but didn't want to chance it. But they are all series connected and it doesn't matter where you choose to feed. So, having the first 4 working, and an empty socket on the last working gauge, I simply removed one end of the nearest jumper and connected it to that last gauge, and it all came to life. That opened the useless loop and gave those gauges power and signal. There is some sort of problem with a couple of them though. Front and rear axle temps and and trans temp. I didn't drive it around enough to warm them up, but they had flashing red LEDs, so I figure there is something up. Owner said 30 years ago we didn't have those gauges, so skip it for now. He needs the truck on the road, but we'll come back and trace it down. It could be a wiring issue, one bad gauge in the string, or even a missing or bad sensor. I'll sort it out when the heat is off. This was just the quickest dumper to get rolling, so it will have to do for now. Everything else I checked seemed fine, except the service brakes; they need adjusting. So the truck guys got it back for that. They will go over it and see what else it needs. Thanks for the help, guys.