Frank McElroy

Its is very likely that the relay controlling the AC is bad. These relays aren't FLA relays designed to switch power to the AC units. They were supposed to be controlling the low voltage input from the thermostat. But that's not how Monaco wired them. That's why we see a lot of folks posting that their board has failed. Honestly, the power management system is a nice convenience but if you know your shore power output and what high draw units you have on the same circuit, you can manually do the same thing that the EMS does automatically. Now, if you want to repair your bad circuit board, I'd first measure the resistance between the power pins and the relay contacts and the relay coil to the controller to be sure the board is good. If you hear the relay clicking but no power output to the AC then you know that the control circuit is good. On the top of the relay, you'll find a part number. A google search will likely get a hit. There are a few good electronic supply houses where you'll likely find a direct replacement. I like Mouser and DigiKey. There are other good ones out there too. The rest will depend on your soldering skills. If you don't have a hot air soldering station, you'll need to first remove the solder from all relay pin connections with a solder sucker or braided copper solder removal wick. Alternatively, most local computer repair shops would likely remove and replace the relay for you.

This is a bit of an unusual repair story so I thought I'd share it. Received a private message from a member with a 2007 Dynasty that the windshield passenger side shade would go up but not down. The driver's side shade worked just fine. He correctly diagnosed the problem as being an issue with the Intellitec PCB #11 in the front run bay. Not being able to find a replacement at a salvage yard, he sent it to me for repair. I initially thought it was a failed relay but nope, a corroded trace on the PCB was the problem. I fixed the board by adding a wire to the back side. This is the first time in a long time that I found a problem to be a bad trace on one of the PCB's in the FRB. This is a good example of making sure power is getting to the relay before just assuming that you have a bad relay. 38040029 (Schematic, FRB Board 11).pdf

Likely your 2004 will have 2 ping tanks on the steer axle air bags. One on the DS and one on the PS with each tank feeding the two airbags on each site. Air is fed to the ping tank from the ride height valve or from your HWH / Valid Power Gear systems in travel/level/manual mode. The purpose of these ping tanks is to add air volume to the airbag system. This helps soften the ride up front. Signature models also have ping tanks on the drive axle air bags. Dynasty models don't have ping tanks on the drive axle air bags.

Keep in mind that most of the braking on these coaches is not like cars. Your primary braking is on your drive axle. That's where your weight and braking is located. What's important is to be sure your manual and automatic slack adjusters are properly serviced and you descend downhill in the correct gear and correct engine brake configuration. Changing steer axle from drum to disk would not be on my to-do list for your coach. Learning how to drive down hill or buying a coach with a Jake brake and disk drive axle brakes would be.

Yes, that is very common for motorhome use. The idea is that the useful life in terms of miles driven for a motorhome is no where near that of a commercial truck so the axle ratings were uprated giving a cost savings to motorhome manufacturers. Parts should be referenced to the actual manufacturer label on the axle.

The male fitting is for the tow truck driver to supply air to the WET air tank on the coach to release the parking brakes and provide air for the air suspension system. The female fitting supplies air from the DRY air tank to air up your tires. I have seen cases where a previous owner changes out the male fitting to a female fitting to air up tires from the WET air tank not realizing how the system was actually designed.

Yes, your Dynasty does have two ping tanks on the steer axle. Over the years, I seen a few reports where one of the 4 large diameter braided hoses going between the air bag and the ping tank develops a leak. Finding the leak requires spraying lots on bubble soap on those hoses. When looking for leaks, these flexible braided hoses are easy to overlook.

Thank you - I'll add this to the next parts list update.

Great informative video. I always cut open my filters every time I change them. The Onan fuel filter is a bit unique. There are two stages inside that rectangular case. In the attached picture, the upper portion shows both the front and back side of the long pleated primary filter media. The lower filter shows both the front and back side of the internal secondary filter. So basically this Onan fuel filters is two filters inside the same housing. In case you are wondering, there was about 1,000 hours on this fuel filter. After cutting open engine fuel filters and finding almost no deposits on the primary and basically none in the secondary filter, I let the generator fuel filter run longer. Anyway, that's been my experience but by coach sites inside a humidity controlled garage when not being used.

Thank you for posting this solution. The basic backbone of the Kongsberg chassis multiplex system is good as long as you have good J1939 databus communication. The weak points are 1) the MOSFET from the front CCM that feeds 5vdc to the smart wheel keypads (there is an aux 5vdc supply fix for that issue) and 2) the obsolete Eaton dash switch modules that can now be repaired and reprogrammed if you can't find a replacement in a salvage yard. Unless hit by lightning, CCM modules rarely fail. It's absolutely critical that on Kongsberg chassis multiplex coaches you don't let your house batteries go dead slowly while being stored or sitting at a repair shop and not plugged in. It that happens you run the risk of burning out one or both master dash switch modules. If you lose a master switch module, about half of your other switch modules connected to it won't work.

Thank you for posting the solution. This information will help others. Glad I was able to help.

Gary, thank you for sending me your schematics. I compared all them to the 2007 set and what you have is identical to what we are calling 2007. The only differences are that the 2007 set has 3 pages for the index and your set has a cover page saying that the set is for 2008. So, basically the 2007 set of wiring diagrams should also apply to 2008. I'll update the file description.

Although we don't have a 2008 wiring diagram in our Downloads, the 2007 wiring diagram should be close. Click on the title to get an option to download all pages in one file.

Here is a picture of the new strut part number on the coach. It matches the invoice part number except the force is shown in newtons. (157 Lb = 698 N) So, basically 700 N.

This is the part Monaco sent me it's a 157 Lb strut. I'll check the part number actually on the unpainted strut.

I'd add about 4 more psi to the tag and get a reweigh. This will give you a good idea of how much of a change in the tag PSI effects the drive and steer axles.

Yes, that is correct. That blower should work to heat the coach with the engine heating loop. Since the engine is heating the aquahot water, all the other heat zones should provide heat with the engine running. However, if it's really cold outside, you still might need to run the aquahot on diesel to heat the coach while traveling.

I'm not sure if on your 2006 you have a separate fan speed switch in the galley or if your fan speed is controlled by keypads feeding input to the Intellitec multiplex system. Attached are a few specific wiring diagrams that should help identify which system you have and how this blower motor is powered. 2006 blower motor Aqua Hot.pdf 2006_Dynasty_Wiring_Diagram p131.pdf

Like Ivan said, when weight coach it's important to have the engine running. The system must also be in travel mode. If the system is off, your axle weights will not be accurate.

Thank you for the very kind words. On this site there are a number of technical experts. My focus is on mid 2000 and newer Dynasty and above models with Cummins engines and house Intellitec and/or chassis Kongsberg multiplex systems. There are a lot of other members far more experienced than I on other model year coaches and systems. That's what makes this forum great - other expert members freely share their own technical expertise. Often folks ask - did I work for Monaco or Cummins. The answer is no. My knowledge is based on owning a Monaco Dynasty (bought new) over 17 years ago and doing all my own service and repairs. (I've owned class A RV's since 1986.) With over 60,000 miles, my coach has never seen a repair shop. All of what I know is based on reading manuals and using that information to maintain and repair my own coach. By training, I'm actually a PhD chemist who spent a 35 year career at Exxon (later ExxonMobil) ending as an Executive Manger in Corporate Research. Most of my electronics background comes as being a Ham Radio operator who built my own Heathkit station in the early 70's and the microcomputer system I built in and machine code programmed in the mid 70's to get my PhD degree in electrochemistry. Yes, Tom Cherry and I talk multiple times a week. We are close friends and we do share and sometimes debate solutions to technical questions posted on the forum. I thank Tom for posting our conclusions because I often just don't have the time. I reply offline about as much as I post online to questions for forum members. There are times where an offline discussion is far more beneficial in transferring technical information than the back and forth online postings.

Many years ago I had a similar situation. After taking my foot off the brake pedal, the car would pull to the left. Found the problem to be the flexible brake hose connected to the front left caliper. In effect the interior hose liner was acting as a check valve. It happens.

I don't know how far back Monaco installed a spare harness and empty conduit. On my coach I have it but it's not shown in my set of schematics. I had to go back to an older model year to find it. On my coach the empty grey electrical conduit is about 1" in diameter, and located up high next to the PS frame rail and accessible from behind the steer axle to in front of the drive axle. It runs through all the storage bays. Spare Wiring Harness.pdf

I agree. Actually I have a ML-ACR sitting on my work bench ready to replace my Big Boy the next time it needs cleaning. I just need time to do it. I like being able to decide from the driver's seat when to engage and disengage it. As for extra wiring, most Dynasty and above coaches have an open conduit from front to back for extra wiring if you already used the Monaco installed prewiring harness not already used in the RRB and under the dash.

I don't see much of an advantage in periodically cycling the big boy but if you do be sure to do it under little if any load. When I'm camping, every few days I'll check the chassis battery voltage to be sure big boy is working and the chassis batteries are being charged. When driving, I'll keep an eye on the house battery voltage to be sure the engine alternator is charging them through big boy. When in storage and plugged in, I bypass big boy with a copper strip and unplug the 8 pin connector on the side of PCB#6. This will charge both the house and chassis batteries and shut off power to the big boy coil. Attached are a few pictures.

BTW, one trick to try while connected to shore power and big boy is engaged (hot) but current is not flowing through it is to cycle the chassis battery disconnect switch such that big boy disengages and re-engages. More likely than not, you will get an internal contact good enough to get by until you have time to clean it. Over the years, this trick has helped a number for folks get back on the road.