2000 mci Auxiliary heater

[Jtussler]

Recently bought a 2000 MCIJ 4500 it has an auxiliary heater there's a control panel under regular heater panel does not light up or work was wondering if anybody Can shed some light on this I would like to get running and can I also use this heater to heat the bus if I tap in to lines

[buswarrior]

Check for disconnected plugs.

On the aux heater and in the outside electric panel under the driver.

Popularly, the plugs get pulled instead of fixing the heater...

I would automatically prepare to do a complete preventive maintenance job on the aux heater, previous owners are notorious for not doing maintenance...

Do you have the manuals for your bus?
You are going to need them!

Happy coaching!
Buswarrior

[Jtussler]

Don't have manuals but I did here it running one day when working on bus is this normal where can a guy get manuals

[Jtussler]

Bus was running when I herd heater

[ktmossman]

MCI J4500 Manuals:

Go to http://mcicoach.com/parts/publications.htm.  To the left of the picture of the bus, there is a "Login as Guest" link. On the next page, select Guest Access.  From there, there are a couple way to search for documents.  For my 2006 J4500, the VIN search didn't work, so I used the other path and narrowed it down.  You can get a whole mess of documents from parts manuals (three massive pdfs) to operators manuals and maintenance manuals.  (If you are a bit web savvy with urls, you can actually get to the root index of the document storage.  However, the file naming conventions are not intuitive.)

Here is what I did NOT find: Detailed electrical schematics (which port in the MultiPlex goes to which function), or "How to" mechanical procedures (that a person the shop would use to price/execute a job).  I know both of these exist because I have spoken with people who have used them.  I am still trying to get my hands on them.

[Jim Blackwood]

You can also search the DL3 threads here and find a lot of good info about these heaters. For instance, I removed the timer controller and substituted a cheap chinese ebay thermostat that cost maybe $15. It changes the functionality of the heater and the way it operates.

Here's the thing, that heater was installed to preheat the engine and keep it warm. Heating the coach was a side benefit. So the controls and plumbing are all wrong for RV use. It is fixable of course and several of us have been working out the details about how that can be done. Currently there is the simple approach, and the sophisticated approach. One thing I have recently noted is that when the main power dicsonnect switch is thrown the aux heater powers up and if the controller turns it on, the circulation pump runs but fans do not. So it preheats the engine but not the coach, until the dash power switch is thrown. Fine for an OTR bus, not so great for an RV. At this point power consumption of the heater fans becomes a concern and we go on from there. Ultimately the fans should run off the house batteries and be controlled by the thermostat or a controller circuit that uses a thermostat.

Then of course you have the tie-in with the engine temperature and I'm unsure of how this works but presumably the engine controller asks for heat as needed. The wiring schematics should show that, but in the case of multiplexed controls may not, especially if the preheat timer is multiplexed. However, I believe some of the newer preheat timers include a thermostat function so yours may be fine with a little reprogramming, possibly with some rewiring of the heater fan power source tied to the house batteries instead of the chassis batteries.

Plumbing is a whole 'nother issue.

Is your heater unit an Eiberspacher or Webasto? Just curious. In either case the controller may say Esper.

Jim

[ktmossman]

More info...

On the MCI site, there is also a "Schematics" section which provides all of the Electrical, Hydraulic, and Pneumatic Schematics for download.  Similar access and search features as I referenced before.

[Jtussler]

Heater is a Spheros

[buswarrior]

MULTIPLEX...

There is nothing you can do without that being the first question, and included in the answer.

There is little to no help written yet on these boards, as there are precious few busnuts having ventured into it, and it isn't readily explained, when you do figure out the little corner of the coach that you think, hope and pray, that you got working "right"

Multiplex wiring and engine emissions control systems between them, are going to knock the crap out of most busnuts of the future.

That being said, the moderated boards are your only help, i sure as hell would not seek multiplex help on social media...

Ask here, and report back here to help those who follow!!!!

Happy coaching!
Buswarrior

[Jim Blackwood]

Probably the worst part of MCIs newer than late 90's, multiplexing was one of those great concepts that probably should have been held back for awhile. Now the trend is towards wireless and who knows where that will lead. But ultimately both hold great promise. It's just that the implementation has been a little shaky. Maybe for the Millennials it'll be no big deal but right now it's a concern. I think the common consensus is that it's best not to mess with it. Because if you do, no regular service guy in the world is going to want anything to do with it. What are the choices then? Realistically, leave it alone. Either that or go to school on it and become the expert. But if you do you will have to continually refresh your memory somehow. A third choice may be to revert to wires but that's a hard sell too and not very practical.

Is it hard to learn? Who knows? You could be the first.

Jim

[richard5933]

For the benefit of those of us still working with copper wires and relays instead of computers on our buses, can someone explain what the Multiplex system is? I'm trying to follow the conversation, but it's hard without know what we're talking about.

[DoubleEagle]

Here is a fairly good explanation: https://familyrvingmag.com/2016/09/01/multiplex-wiring-systems/. It might very well be a great idea to increase connectivity and reduce the number of wires, but it also requires computers and other exotic relays that only trained people can figure out. It seems to me that if there is a corrosion problem or fire, the functions of many items could be wiped out. I'll stick to one wire, one function, and self diagnosis. Relying on the DDEC system for the engine control is scary enough. 

[luvrbus]

the auxiliary heat is a Proheat on a 90 minute timer on a J4500 if the burner is on it will light a tell tale light on the dash (heater) if you have the engine running the the temperature-dependent control will override the timer push the switch forward it turns on the engine pre heat pushing the switch back turns the Proheat off after it purges for a few minutes and it is not tied into any of the multiplex system,If the ProHeat is not firing locate it and on the control module it will have a self diagnostic displaying the codes simple huh