Bradley

Hi Frank, just who I was hoping to hear from! Yes, that’s correct I am still measuring 120 ohms across pins C & D at the rear data port in the engine bay. You are correct that I only have a 9 pin port capable of accessing the j1939 data system the rear, and I have a 6 pin j1708 port under the steering column area. My Aladdin system does also utilize the slower (but still functioning) j1708 data bus as I’ve followed these wires to the controller under the dash. But- Interestingly enough my Actia dash gauges are in fact fed by a single j1939 data line. It runs up through the drivers side armrest over the top of the FRB, and plugs right into the triangular deutsch connector on the harness on the back of my Actia cluster. I did not take a photo of that- but I will. You can see why I am so stumped. Does not make sense all my major systems are online yet at the “end” of the j1939 run my Actia gauges do not function. Through much troubleshooting I do not believe I have an Actia problem. Is it possible in my 2006 model year coach that my major systems communicate over the j1708 data line and my j1939 data line is really only for dash gauges? That goes against all I have read on this subject, but I’ve really not been able to find much specifically about 06 model year Monaco’s with this same issue. I have though read that 06’ was a transition year from the slower j1708 data bus to the j1939. Just a thought. ? Would explain why all my systems are online though..

Am I chasing the wrong issue? Should all this tell me this is a problem internal to the ecm, or internal to the warning bank on the dash? Just looking for more opinions, and knowledge. Thanks in advance

Ok. This has been a long time coming, have been working on other projects, and it’s wet and cold here in the Pacific Northwest. I’ve driven my 06 Dynasty about 850 miles since this gauge swinging / communication error has begun. It shifts right, and drives great. Allison shift pad is illuminating correctly, and the Cummins is starting easily & running exactly right still per the Aladdin display. I still have ATC, and engine brake functions normal. I have hunted, for hours to find the terminating resistors. I have still found none. ( Also tried a new master speedo gauge to no avail ) I dug for hours with my entire dash torn apart and followed the single j1939 wire that runs directly into the back of my Actia instrument cluster- I followed it out the floor of the drivers armrest all the way through the fuel bay into the basement of the coach. No resistor in line. I did the same in the rear of the coach. It’s possible I could still be missing it back there, but I don’t believe I am. I have taken down basement ceiling panels again and have found these mysterious J1939 connections (pictured) which are not connected to anything. You would think this would be a Smoking gun. They are in the center bay which has many chassis components (Bendix ABS, Allison TCM, and leveling box) I have poked around and there are not resistors or connections, anywhere down here for these to plug into. There is also a white wire coming from the rectangle shaped deutsch connector which also does not have anything to connect to. I dug in the ceiling of the neighboring bays as well. I also think it’s odd that some of my j1939 lines are double wired? All the others I have seen on these forums are one single data cell line from front to back. Mine has two put together (so 2 data cell lines, 4 twisted wires) running from the rear to this bay, and a single running to the front gauge cluster. Is it possible the resistor was never put in line out of the factory? I bought this Dynasty from my grandparents who bought it brand new back in 06. I know all of its history, and they never had any work done which involved removing basement panels for any reason, they also never had any communication errors in the lifespan of the coach until shortly after I purchased it. So these connectors have been this way since it rolled out of the factory presumably. Should I try plugging a resistor into the triangular deutsch connector in the basement? Could it harm anything? The whole situation is a head scratcher. Hard to believe these would only just now be causing an issue more than 15 years later. I will attach some pictures (and will try and take some better ones). Sorry for the long winded recap, and repeat of some info- but I’m determined to figure this issue out myself, and not pay a tech to chase a problem they may not find either. Felt like I should add, if there was truly a major communication failure, across all systems as the gauge cluster says , how would it be starting, running, and driving correctly? I know there is more than one data transferring system on a 2006 model year, which is why my Aladdin is still displaying engine and transmission parameters it does not use the j1939 data line (j15708 I think?) But from what I have figured out, the transmission control module, the ECM, and most chassis components use solely the J1939? I read on another forum that someone had a very similar problem on an 06 Signature Series, and their ECM was the culprit. But they were missing the gear readout on their Allison shift pad, and they had no engine braking. My systems all work as normal. I also read it is possible on some Cummins ECM’s that one of the termination resistors is an internal part to the ECM?

Following this thread to see where it goes as well, on my 06 Dynasty step and grab handle lights only come on when I use the remote for the keyless entry, but when I use the switch on passenger armrest, they do not light. Been like this for years. Switch used to work correctly. The issue has always had me pretty stumped

Thank you very much! Continuing my search in the morning!

Hi there, I know this thread is over a year old… but having identical problems with my gauges on my 06 Dynasty- my hours of troubleshooting is also pointing me to bad resistors. Still runs and drives normal. Did you ever get to the bottom of this? Thanks in advance!!

Ok, measured the ohms at pin c & d. 119-122 ohms steady. Found two more j1939 connectors about 6-12 inches upstream of the rear diagnostic port, but still cannot locate the terminating resistor. Seems that must be my issue, so I’ll keep searching. Anyone who might know an exact location of either resistors on an 06 please chime in! Although I’ve gathered Monaco never really built two coaches exactly alike, so I may just have to hunt them down. Frank, if at all possible could you post some photos of what your resistors look like? I’m assuming they look just like the triangular Deutsch connectors that the rest of the j1939 line uses? I pulled dash panel, again, and the j1939 line there runs directly into my Actia gauge panel, unless the resistor is branched off somewhere else a little further under the dash? Like I said I know our coaches may be a little different, just looking for some more direction!! Thanks for all your help!

Hi Frank, no I do not (yet) have a code reader for the motorhome. In my research in the last few weeks I have found out my Aladdin still displays because it actually pulls the info from a slower data line (I forget the name) that is separate from the j1939. And because I have no starting / drivability issues a lot of this evidence points towards one or both of these resistors, which I’ve also read can be somewhat sensitive to a jumpstart. I’m going to use my multimeter when I get home today at the rear diagnostic port ( pin C and D if anyone is wondering) to measure the ohms and go from there. I highly suspect - and hope, that this is the issue I’m having. Have you ever seen these resistors on your 08’?

Hi there, sorry I’ve been slow to come back to this thread, it’s been a whirlwind few weeks of trips, and work. After so very much research and wire tracing most of which came to no fruition solving my issue with my dash gauges, I have now discovered I believe my issue is with the terminating resistors (one or both) at the ends of the j1939 data line running the span of the coach. This is the only logical thing left to check, and makes so very much sense since the engine and trans still run flawlessly. My question before I do even more crawling around is if anyone here knows where these two terminating resistors might be located in an 06’ era Dynasty. I know I need to follow the data line from end to end and they will be there somewhere, but 42 feet is a lot of searching! I am going to check for sure by measuring the ohms on the data line, it should be about 60 ohms if all is correct, zero, or 120 ohms and I’ve got a bad resistor(s). Chime in with any suggestions where to look first, I’m going to start at the rear engine diagnostics port and work my way forward from there! Thanks in advance!!

MODERATOR's EDIT. There is a topic that Bradley started and he did the research and found this one. Here is the current topic. In order to NOT have two topic combined...It is requested that any comments that would be made here be made on the current thread. Thanks for understanding and to help dual posting and avoid confusion. Mike, I know this is a few years back, but I’m having they very same issue on my 06 Dynasty. Not exactly sure what system the 08 Signature has but did your Aladdin/ silver leaf still show engine parameters when this happened? My gauges are doing the EXACT same thing, engine runs fine, but Aladdin still shows all parameters from engine and trans. I would think if there was en ecm connection issue Aladdin would not show? Just wondering if ECM connection should be my next avenue to check. Thanks!

Sorry I took so long to reply to this thread, have been working non stop in preparation for our trip! Wow, thank you all for the wealth of knowledge you’ve left me to diagnose this problem!! So many kind people on this forum. Seems I have several things to try. The first is going to be the simplest by disconnecting all power for an hour as suggested. I have tried it, but did not cover the solar panel, and only waited 20 minutes. I will also try some of the diagnostics for the gauges themselves as found in the manual that was posted. Seems like that could potentially rule out of its gauge issues? I do believe since the Aladdin is working it must be an Actia issue as well. I’m not sure if that’s a good thing or not! I have lots of trouble shooting to try this weekend, and will report back my findings. Thank you all so much!

Hi there, I’m suddenly having issues with the gauges on my 2006 Monaco Dynasty Diamond IV. All the gauges EXCEPT the fuel and air gauges are sweeping constantly and I’ve got check engine, engine comm. failure, trans comm. failure, and check trans light. I will say this issue started after engine batteries dying and jump starting the coach. Coach batteries were only 13 months old, but a defective big boy solenoid in the RRB caused them to die. I replaced big boy and chassis batteries for peace of mind. I have spent countless hours looking for the obvious, and not so obvious. What is interesting is my Aladdin is still showing all engine parameters correctly, RPM, speed, boost, oil pressure, voltage, etc. I also drove the coach 40 or so miles at highway speeds in order to get it home and it drove normally, but the gauges did this the whole way home. I’ve taken basement ceiling panels down and tried to trace broken wires or burnt fuses to no avail. Though I did find mouse evidence I did not find any chewed wires. I’ve also checked all fuses and connections in both the front run box, and rear run box. Has anyone else had this problem on a similar year Monaco/HR/Beaver?? Any and all suggestions appreciated! I should add, I have tried cleaning grounds, another hard reset of all systems (coach house, and chassis systems all disconnected for more than 20 mins) and also tried adding another large ground wire to the ground wire going into the gauges. I even ordered a new (used) Actia master speedometer gauge thinking this may have been my issue. Still no dice. Supposed to leave for a 10 hour trip across mountain passes in Wa state next week. Starting to get frustrated now. I’ve traced wires for many hours and found no breaks or corrosion. I have not been able to locate any more J1939 Deutsch connections other than one directly behind instrument cluster, and one in the center bay ceiling. Both were tight with no corrosion. Is there more near the engine? I wouldn’t think the Aladdin would be displaying engine and trans parameters if there was an ECU connection problem? Someone else out there with an 06 Monaco has to have had this same issue…