New Owner 2000/01 Diplomat. Tons of Questions.....

[Fffrank]

Picked this up and road-tripped it back home this weekend. I'll be the 3rd owner and it's in wonderful shape. Lot's of care taken by the previous owners. 71,000 miles. 180hrs on the genset.



I've been over both the spec sheets for the 2000 and the 2001 and it seems to be a mix of the two. Color scheme is 2001, trailer hitch is 10k lbs (2001 spec) but leveling control lacks the auto button (which seemed to be added in 2001. It has the "upgraded" ISC engine but I'm not sure which spec. 2000 was rated as 315hp while 2001 was 330hp. This one seems to have checked every option box.

I've got a laundry list of questions/issues and this forum seems like the place for answers. I'll also try to keep this thread updated as I work on various projects/upgrades.

- Air System. There is a leaking fitting at the front of the bus that I can hear when you turn the engine off. It's attached to a blue electrical solenoid in the very center of the bus. Maybe this controls the step cover (which we had an issue with at one stop that we haven't been able to reproduce.) Can I buy a replacement fitting anywhere locally (Napa/Autozone/Oreillys/etc) or do I need to order one online?

- The owner did have the rest of the suspension system inspected recently and they gave it a thumbs up but I'm worried it loses pressure too quickly. No problem while driving but if it sits overnight the air bleeds out. Normal?

- The Air Dump button works but is SLOW. The coach only drops 3" when all of the air is dumped. Seems like the step is still quite high at 12" above ground. Normal?

- Basement heat. I haven't investigated this but can anyone tell me where I would find if there is an aux heater in the wet bay?

- ABS Light. Previous owner said he has had an intermittently on ABS light for 5 years. He said dealership investigated several times and was never able to find a problem. Eventually he got sick of paying for diagnosis and learned to ignore it. Light is now on full time. I suspect it's a wheel sensor -- is there a way to scan/diagnose which wheel it may be?

- 2nd Thermostat. There's a digital thermostat that has a mode for HEAT/FAN/AC but right above that there is an analog thermostat. Anyone know what that controls?

- Rooftop ACs. Do these have electric heat as well? Or is my only heater the propane furnace?

- Blower motor switch. Dash heat/air fan speed switch only works on HIGH or OFF. I seem to remember this being a common problem in vehicles but not sure what the fix is. Anyone?

That's it for now! Tackling new flooring and figuring out just how much we want to update the cabinets. They are in absolutely PERFECT condition but that honey oak look is just so dated. Struggling for how much work we want to do to make them feel a little fresh.

[JJTL]

Originally Posted by Fffrank

I've got a laundry list of questions/issues and this forum seems like the place for answers. I'll also try to keep this thread updated as I work on various projects/upgrades.

- Air System. There is a leaking fitting at the front of the bus that I can hear when you turn the engine off. It's attached to a blue electrical solenoid in the very center of the bus. Maybe this controls the step cover (which we had an issue with at one stop that we haven't been able to reproduce.) Can I buy a replacement fitting anywhere locally (Napa/Autozone/Oreillys/etc) or do I need to order one online?

- The owner did have the rest of the suspension system inspected recently and they gave it a thumbs up but I'm worried it loses pressure too quickly. No problem while driving but if it sits overnight the air bleeds out. Normal?

- The Air Dump button works but is SLOW. The coach only drops 3" when all of the air is dumped. Seems like the step is still quite high at 12" above ground. Normal?

- Basement heat. I haven't investigated this but can anyone tell me where I would find if there is an aux heater in the wet bay?

- ABS Light. Previous owner said he has had an intermittently on ABS light for 5 years. He said dealership investigated several times and was never able to find a problem. Eventually he got sick of paying for diagnosis and learned to ignore it. Light is now on full time. I suspect it's a wheel sensor -- is there a way to scan/diagnose which wheel it may be?

- 2nd Thermostat. There's a digital thermostat that has a mode for HEAT/FAN/AC but right above that there is an analog thermostat. Anyone know what that controls?

- Rooftop ACs. Do these have electric heat as well? Or is my only heater the propane furnace?

- Blower motor switch. Dash heat/air fan speed switch only works on HIGH or OFF. I seem to remember this being a common problem in vehicles but not sure what the fix is. Anyone?

That's it for now! Tackling new flooring and figuring out just how much we want to update the cabinets. They are in absolutely PERFECT condition but that honey oak look is just so dated. Struggling for how much work we want to do to make them feel a little fresh.

Congrats on the new coach, Frank!

Here is a copy of your owner's manual, in case you don't have one: https://www.monacocoach.com/resource...1_Diplomat.pdf

If you look on page 235, it will show you how to retrieve the ABS fault code. This will tell you what the issue is, and if applicable the wheel sensor location. We have been chasing an ABS issue ourselves for sometime, these systems are finicky. At some point, you decide whether the constant service shop bills to try and fix it are worth it.

For the air leaks, it depends what 'normal' is. For a 20 year old coach, it sounds about 'normal' . Ask me how I know . In our thread you can see some I've tackled already. But ideally, a tight air system should go weeks before noticeable air loss. If it's going down in minutes or even hours, then there is a decent size leak somewhere. I don't know enough about your particular coach and chassis to help with the blue valve, but maybe a picture would help.

As for the AC heat pumps, air suspension drop and basement heat, hopefully someone more familiar with your coach would be more helpful.

The analog thermostat is likely for a kitchen air extraction vent.

Hope that is somewhat helpful.
Enjoy the new coach and the renovations!
Josh

[Fffrank]

Thanks for the help! I do have both the 2000 and the 2001 owners manuals and like I said before, my coach seems to be a mix of the two (but the 2001 manual is MUCH more comprehensive than the 2000.)

Originally Posted by JJTL

At some point, you decide whether the constant service shop bills to try and fix it are worth it.

This is exactly what the previous owner told me. He said he spent $1500 over the years with the dealer trying to fix the ABS and then just decided he didn't need it. He apologized and wished me luck in tracking the problem down.

[gsgriffin]

Originally Posted by Fffrank

Picked this up and road-tripped it back home this weekend. I'll be the 3rd owner and it's in wonderful shape. Lot's of care taken by the previous owners. 71,000 miles. 180hrs on the genset.



I've been over both the spec sheets for the 2000 and the 2001 and it seems to be a mix of the two. Color scheme is 2001, trailer hitch is 10k lbs (2001 spec) but leveling control lacks the auto button (which seemed to be added in 2001. It has the "upgraded" ISC engine but I'm not sure which spec. 2000 was rated as 315hp while 2001 was 330hp. This one seems to have checked every option box.

I've got a laundry list of questions/issues and this forum seems like the place for answers. I'll also try to keep this thread updated as I work on various projects/upgrades.

- Air System. There is a leaking fitting at the front of the bus that I can hear when you turn the engine off. It's attached to a blue electrical solenoid in the very center of the bus. Maybe this controls the step cover (which we had an issue with at one stop that we haven't been able to reproduce.) Can I buy a replacement fitting anywhere locally (Napa/Autozone/Oreillys/etc) or do I need to order one online?

- The owner did have the rest of the suspension system inspected recently and they gave it a thumbs up but I'm worried it loses pressure too quickly. No problem while driving but if it sits overnight the air bleeds out. Normal?

- The Air Dump button works but is SLOW. The coach only drops 3" when all of the air is dumped. Seems like the step is still quite high at 12" above ground. Normal?

- Basement heat. I haven't investigated this but can anyone tell me where I would find if there is an aux heater in the wet bay?

- ABS Light. Previous owner said he has had an intermittently on ABS light for 5 years. He said dealership investigated several times and was never able to find a problem. Eventually he got sick of paying for diagnosis and learned to ignore it. Light is now on full time. I suspect it's a wheel sensor -- is there a way to scan/diagnose which wheel it may be?

- 2nd Thermostat. There's a digital thermostat that has a mode for HEAT/FAN/AC but right above that there is an analog thermostat. Anyone know what that controls?

- Rooftop ACs. Do these have electric heat as well? Or is my only heater the propane furnace?

- Blower motor switch. Dash heat/air fan speed switch only works on HIGH or OFF. I seem to remember this being a common problem in vehicles but not sure what the fix is. Anyone?

That's it for now! Tackling new flooring and figuring out just how much we want to update the cabinets. They are in absolutely PERFECT condition but that honey oak look is just so dated. Struggling for how much work we want to do to make them feel a little fresh.

Might not have all of this correct, but your rig should be similar to mine.

Check to see if the air-leak is coming from your air release valve. When you let out air using the switch, it is slow, and it should come from a solenoid valve mounted on the outside of the firewall above the generator. Look for leaking hoses or may need to replace that solenoid.

The air will release and low the rig when your jack are not down. Try pushing the breaks several times to release more air faster.

The analog thermostat could be connected to a ceiling fan. Mine had an analog that you could set and if the temp went over, the ceiling exhaust fan would kick on. I got rid of that and installed different automatic and remote control ceiling fans with built-in thermostats.

My heater in the water bay is back under and behind everything. Looks like a small ceramic heater, but it is 12v. Kinda special and not cheap. My Monaco has the control to turn it on in the master panel, but it only turns on when below freezing.

I would be concerned about the ABS. In many cars, when the ABS comes on, that means that it is not working at that time. It may also mean that a hard press on your breaks and you could have a skid....not only bad for control, but it will flat spot your tire and give you a bumpy ride.

The roof AC may have a "heat pump". When you scroll through the options on your digital thermostat, look for that option. It basically runs the AC in reverse (to over simplify it).

Air should not bleed out of the system and be gone by morning. Check the first point about where you hear that sound. A mechanic trick is to get a flexible tubing and hold one end to your ear and the other to sniff around for the exact point of the sound. So long as your rig has 120lbs air pressure, you are good to drive. When pressing the brakes or using the horn, you do reduce the pressure and it should build back quickly if driving and have reasonable RPMs.

If you are compressing air a lot, you may want to check your air dryer filter. That may want to be replaced. Check by releasing some air with the valve in the front generator bay and release air...if you see moisture, you need a new filter. You do NOT want water sitting in your air tanks.

Hope that helps. I've had my Monaco for 4 years and have modified it a lot, added a lot, done all the maintenance myself, and continue to explore and learn. If you like working on things, this is a gold mine. Monaco (arguably) is one of the best built rigs in this era. Very solid and lots of great value. Every time you have to fix or repair something, just know that many of the new rigs spend a lot of time in the shop as well. Some spend a significant amount of their first year in warranty repair. Looks like you have a good rig, but plan to keep investing in it every year to keep it up and improve it. Not a free ride, obviously!!!

[Outbound]

Congrats on your new RV, hard to answer your questions without model number of air conditioners, model number will tell you if you have elec. heat in a/c units.

[8.3Oilbuner]

Hi Fffrank; Congrats on the new to you coach. Josh has given you some great info. The air leak that you hear in the gen. compartment is probably coming from the blue MAC valve that controls the step cover in the coach. Very common problem. There is a bigger blue MAC valve also in the gen. compartment closer to the drivers side that is part of the chassis air dump for the front air bags. The smaller MAC valve gets dirt and rust particles in the valve and leaks air out the bottom exhaust port. There is a replacement valve, but you should try cleaning the valve first before replacement. With some issues you are having, like the MAC valve for the step cover, try using the search box at the top right of this page. That will give you access to others who have posted problems and fixes in this forum.

On the ABS issue, see if you have a module in the front electrical bay under the drivers seat outside the coach. It will have a small diode lit when the dash ABS light is on at the dash. There is a test button on that module to test and retrieve ABS problem codes from the system. These modules can go bad, but can be rebuilt. Check the 2 fuses on the module to see if they are OK. Again, use the search box at the top of the page for this problem as others here have written on how to get the ABS codes.

Dash heating and A/C fan problem is that the resistor pack on the blower housing has burnt out. Common problem. It is a Ford part and you can find them at auto parts stores or on the web. Part number should be, D8BH-19A706-AB or D32H-19A706-AB.

This should get you going. You will be an expert in not time! P.S. Mud wasps like to make mud nests in the exhaust ports for the chassis air bag dump valves. Makes the valves slow to exhaust air from the valve.

[JerryLook]

Hey nice looking Monaco! I bought a 2000 Diplomat a couple months ago too. It’s funny because I have some of the same issues/questions that you do. My ABS light is on, and my air system goes down within a couple hours of turning off the engine. Also I have the same dash HVAC issues.

My RV also has the 8.3 ISC, and the leveling system does not have the auto function. From what I’ve read the standard engine was a 5.9L, and the 8.3L was an option.

I’ll be watching you thread closely so maybe I can fix some of my issues too

[Fffrank]

Originally Posted by gsgriffin

Check to see if the air-leak is coming from your air release valve. When you let out air using the switch, it is slow, and it should come from a solenoid valve mounted on the outside of the firewall above the generator. Look for leaking hoses or may need to replace that solenoid.

That one seems tight and I can def see/air coming out of it when the switch is held down. It takes a while but does work. The one I have an issue with is mounted on the same firewall but almost right in the middle.

Originally Posted by gsgriffin

The analog thermostat could be connected to a ceiling fan. Mine had an analog that you could set and if the temp went over, the ceiling exhaust fan would kick on.

That sounds right! The PO did mention that some of the fans were on a thermostat so that makes sense. Thank you! I'll mark that mystery as solved.

Originally Posted by gsgriffin

My heater in the water bay is back under and behind everything. Looks like a small ceramic heater, but it is 12v. Kinda special and not cheap. My Monaco has the control to turn it on in the master panel, but it only turns on when below freezing.

I'll look into this. I don't have the "cold weather package" but believe it is still supposed to have basement heat? If not, it's definitely an upgrade that I'll make.

Originally Posted by gsgriffin

I would be concerned about the ABS. In many cars, when the ABS comes on, that means that it is not working at that time.

You are correct. It is not currently operational and something I'd like to fix.

Originally Posted by gsgriffin

The roof AC may have a "heat pump". When you scroll through the options on your digital thermostat, look for that option. It basically runs the AC in reverse (to over simplify it).

I'll check it out!

Originally Posted by gsgriffin

Air should not bleed out of the system and be gone by morning. Check the first point about where you hear that sound. A mechanic trick is to get a flexible tubing and hold one end to your ear and the other to sniff around for the exact point of the sound. So long as your rig has 120lbs air pressure, you are good to drive.

Did a quick walk-around after shut down this afternoon and did not hear any air leaks except for that front solenoid/valve. I'll continue to investigate.

Originally Posted by gsgriffin

If you are compressing air a lot, you may want to check your air dryer filter. That may want to be replaced. Check by releasing some air with the valve in the front generator bay and release air...if you see moisture, you need a new filter. You do NOT want water sitting in your air tanks.

No moisture to speak of and the previous owner told me he recently had the air dryer rebuilt/replaced.

Originally Posted by Outbound

Congrats on your new RV, hard to answer your questions without model number of air conditioners, model number will tell you if you have elec. heat in a/c units.

I'll see what I can find out! 2000 brochure does not list heat pumps but 2001 model does.

Originally Posted by 8.3Oilbuner

The air leak that you hear in the gen. compartment is probably coming from the blue MAC valve that controls the step cover in the coach. Very common problem. There is a bigger blue MAC valve also in the gen. compartment closer to the drivers side that is part of the chassis air dump for the front air bags. The smaller MAC valve gets dirt and rust particles in the valve and leaks air out the bottom exhaust port. There is a replacement valve, but you should try cleaning the valve first before replacement. With some issues you are having, like the MAC valve for the step cover, try using the search box at the top right of this page. That will give you access to others who have posted problems and fixes in this forum.

It's definitely the smaller one in the center but it seems like the fitting or the hose on the intake side of it is leaking. I'll take it apart and clean and report back.

Originally Posted by 8.3Oilbuner

On the ABS issue, see if you have a module in the front electrical bay under the drivers seat outside the coach. It will have a small diode lit when the dash ABS light is on at the dash. There is a test button on that module to test and retrieve ABS problem codes from the system. These modules can go bad, but can be rebuilt. Check the 2 fuses on the module to see if they are OK. Again, use the search box at the top of the page for this problem as others here have written on how to get the ABS codes.

Great tip, thanks! I'll see what I can find out.

Originally Posted by 8.3Oilbuner

Dash heating and A/C fan problem is that the resistor pack on the blower housing has burnt out. Common problem. It is a Ford part and you can find them at auto parts stores or on the web. Part number should be, D8BH-19A706-AB or D32H-19A706-AB.

Thanks! Quick search and found the location and will verify tomorrow. I knew I've dealt with these before -- the plug is the same as an older Ford truck I had for a long time.

- One more new question for today. I started the coach up to bring it around to my driveway. I know you need to let them "warm up" especially when it's 20F like it was today. But I'm curious if the dash voltage bouncing between 12v and 14v is normal? It seemed to cycle as if the alternator was kicking on and off every 15-20 seconds. As the 14v kicked on, all the gauges would also bounce up and the alarm would get louder... then another few seconds later it would drop back to 12v and all the other gauges would drop as well (including the tach even though I could hear that the engine didn't throttle down.)

Once up to temp the fluctuation appeared to stop.

[Fffrank]

Originally Posted by JerryLook

Hey nice looking Monaco! I bought a 2000 Diplomat a couple months ago too. It’s funny because I have some of the same issues/questions that you do. My ABS light is on, and my air system goes down within a couple hours of turning off the engine. Also I have the same dash HVAC issues.

My RV also has the 8.3 ISC, and the leveling system does not have the auto function. From what I’ve read the standard engine was a 5.9L, and the 8.3L was an option.

I’ll be watching you thread closely so maybe I can fix some of my issues too

Awesome! And yes, the 8.3 was important for me when I started shopping. A friend of mine told me that whatever I bought, do not buy the base engine or the base genset. If you find one that was upgraded it means that the original owners likely ordered a well optioned coach and (hopefully) took care of it as well!

[8.3Oilbuner]

Good morning Fffrank; Glad to see you are making progress and getting some questions answered. The voltage change you are seeing is the operation of the grid heater on the Cummin's engine. When the outside temp drops to a certain temp the 12V grid heater comes on to help with cold engine starting. That heater draws a lot of amps and that is why you hear the engine speed drop and the voltage drop on the dash gauge. The alternator is working hard to make up that amperage. Totally normal.

As you mentioned that air was leaking at a fitting on the step MAC valve. Those fittings are a push and pull to release fitting and you might need to take the plastic air line off and cut the tubing, use a tubing cutter as you want a straight cut, and reinstall to see if the air leak stops. Everything gets bounced around driving these rolling earthquakes and things get loose over time.

Keep up the good work and ask lots of questions!

[Fffrank]

Originally Posted by 8.3Oilbuner

Dash heating and A/C fan problem is that the resistor pack on the blower housing has burnt out. Common problem. It is a Ford part and you can find them at auto parts stores or on the web. Part number should be, D8BH-19A706-AB or D32H-19A706-AB.

Quick and easy trip the auto store and this is fixed. It's a bit of a ship in a bottle arrangement to get it in and out but I've dealt with many worse in boats over the years.

Originally Posted by gsgriffin

My heater in the water bay is back under and behind everything.

Can you tell me where/how you can even see yours? I've come up completely empty so far but my water bay seems to have no access to it. The panel with the dump valves and fill ports is the only access I've found and it doesn't seem like it would allow access very easily for me to service anything behind it (or try to install a cube heater?)

Originally Posted by gsgriffin

The roof AC may have a "heat pump".

Pretty bummed that I don't seem to have heat strips or the heat pump. The good news is that it seems relatively easy to add heat strips to my AC. I haven't found anything indicating the exact model # -- any thoughts on where I can find that info? Also curious how you can reprogram the thermostat to also control heat strips. I understand they don't put out much heat -- but since we are going to be winter camping a lot every little bit will help!

Originally Posted by 8.3Oilbuner

The voltage change you are seeing is the operation of the grid heater on the Cummin's engine. When the outside temp drops to a certain temp the 12V grid heater comes on to help with cold engine starting.

Thank you! I'm a very curious person and so relieved to hear there is a good reason for what I'm seeing!

Originally Posted by 8.3Oilbuner

As you mentioned that air was leaking at a fitting on the step MAC valve. Those fittings are a push and pull to release fitting and you might need to take the plastic air line off and cut the tubing, use a tubing cutter as you want a straight cut, and reinstall to see if the air leak stops.

That leak is gone -- did exactly what you explained. THANKS! Walked around the coach and under each wheel well and couldn't hear any further leaks. I has been sitting in the cold for over 24 hours now and hasn't settled any further past 80psi. Not saying it's perfect but seems better without the leaking solenoid.

New question -- and yes, I did search! I've read so much that I've confused myself!

- I understand that my inverter/converter will charge the house batteries while on shore power or while the gen is running. I understand that the alternator will charge the chasis batteries while the engine is running. In all my years of boating, I've never come across a properly designed system that didn't have a system to "top up" batteries no matter where the power was coming from. Important to me that I fix that!



Am I right that the large relay in the middle is the BIG BOY relay I read about on here? I'm assuming above that is the aux/combine switch on the dashboard?

Is the current best method to "fix" my charging to add a BIRD panel? Does that take care of everything or do I need an add'l devices to also combine while the alternator is running?

[gsgriffin]

Originally Posted by Fffrank

- I understand that my inverter/converter will charge the house batteries while on shore power or while the gen is running. I understand that the alternator will charge the chasis batteries while the engine is running. In all my years of boating, I've never come across a properly designed system that didn't have a system to "top up" batteries no matter where the power was coming from. Important to me that I fix that!



Am I right that the large relay in the middle is the BIG BOY relay I read about on here? I'm assuming above that is the aux/combine switch on the dashboard?

Is the current best method to "fix" my charging to add a BIRD panel? Does that take care of everything or do I need an add'l devices to also combine while the alternator is running?

This is where a Tric-L-Start might help you. I installed this pretty quickly on my RV when I got it 4 years ago. I also got the larger amperage to run to my TOAD when driving. The amperage from the alternator back to the house batteries is not something I do as when I reach a destination, I either have solar, generator, or shore power and don't worry about adding load to the alternator. These are not high amperage and won't "charge" a battery, but they are enough in my experience to not have the chassis battery die.

Mega TRIK-L-START Starting Battery Charger/Maintainer

[gsgriffin]

Originally Posted by Fffrank

Can you tell me where/how you can even see yours? I've come up completely empty so far but my water bay seems to have no access to it. The panel with the dump valves and fill ports is the only access I've found and it doesn't seem like it would allow access very easily for me to service anything behind it (or try to install a cube heater?)

Our rigs are slightly different a few years separated. Perhaps someone else can describe better who has the same model and year. Which model do you have? Do you have a Heat switch on your control panel inside that has a red indicator light next to it? Not sure yours is just like mine, but that may tell you if you have one or not.

My water bay has two doors and a gap below two white panels that all the fixtures hang from. Under that bottom gap is the back is my heater. Typically the surface panels can be removed with a bunch of screws to see what is behind. You can see it barely in this photo on the bottom right. (yes, I installed an RO water system that is not typical).

Pretty bummed that I don't seem to have heat strips or the heat pump. The good news is that it seems relatively easy to add heat strips to my AC. I haven't found anything indicating the exact model # -- any thoughts on where I can find that info? Also curious how you can reprogram the thermostat to also control heat strips. I understand they don't put out much heat -- but since we are going to be winter camping a lot every little bit will help!

For me personally, I got several small electric heaters to use that are enough to keep us warm or just a little extra from the furnace when very cold. Cheap, flexible, easy to store. Just don't try to run two of those on the same circuit at the same time....or your coffee maker at the same time

[CountryB]

Originally Posted by Fffrank

Am I right that the large relay in the middle is the BIG BOY relay I read about on here? I'm assuming above that is the aux/combine switch on the dashboard?

Is the current best method to "fix" my charging to add a BIRD panel? Does that take care of everything or do I need an add'l devices to also combine while the alternator is running?

That is not a Big Boy solenoid (which is used for charging the Chassis and House batteries).

It looks like a "Boost" solenoid - which is used to connect the Chassis and House batteries together to provide additional power for starting in cold weather. If it is a boost solenoid, you would have a rocker switch on the dash marked "Boost" (or "Combine" or similar wording).