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I’m just a bystander when it comes to Marathon specific knowledge but the word multiplex keeps coming up regarding the Marathon conversion.

I know for a fact that Prevost uses a multiplex system in all coaches after late 2006 or 2007 model years in which all communications with the master module for the entire coach are done by a single pair of wires and the entire multiplex system is able to prioritize those communications so critical messages between modules are prioritized and dealt with by the system before non-critical communications are passed. For example the lack of engine oil pressure would likely get a much higher priority, and all system actions related to that such as warning lights and engine shut down would be done before the system passed data relating to the outside temperature reading. These communications are happening in a very fast speed, but are going on at all times and can be anything from the examples above to a communication for the system to do some action such as turn on the lights initiated by the driver.

If Marathon has a multiplex house as seems to be suggested then it would also have various control modules to handle most of the switching, circuit protection, and monitoring with communications to a master control via a similar pair of communications wiring. Does Marathon have multiplex wiring?

[Bill]

Yes, even our 1999 vintage uses Techlon multiplexed signaling and modules throughout the house. Wires are actually RJ45 ethernet cables. There are input and output modules. Some of the output modules are actually what does the pulse width modulation (PWM) to dim lights. One service connector above the entry door can communicate with the entire house network. Marathon calls it Techlink.

The system is pretty reliable. We only had one instance where a module “forgot” its network ID. Marathon was able to reprogram it with their refrigerator sized portable test box for that vintage bus.

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So if Marathon is indeed using a multiplexed system, to what extent are owner made changes going to impact everything from diagnostics to switching functions to circuit protection?

And is the system set up to communicate faults or perceived faults. For example a coach with halogen house lighting that gets switched to LED lighting as is being discussed has substantial differences in loads. Is the system going to recognize those changes to less current draw as a fault such as burned out bulbs, or is it merely functioning as a switching device?

It has been stated only a specific type of LED is an acceptable replacement for lights. Is the system set up so it is diagnosing changes or is the multiplex system also doing and providing an analysis and reporting changes, and if so where is the reporting done?

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I would say it’s a switching device and doesn’t seem to care about the change in amperage or load.

[Bill]

In our bus the Techlon output switches for the lights each support two channels of 4-5 lights. The dim level is set via the light switches and input multiplexers and communicated over the network to the output switches which then simply pulse width modulate the output. There is a fuse per channel and an error LED but I believe that reflects its SW/network status rather than an output error analysis. Pretty sophisticated for late 20th century vintage.

I don’t think a user could easily modify or expand the system without Marathon help. There are some unused light switch positions that probably could be programmed to perform new functions but one would have to add the output modules and program them. My bus even has a (land line) modem that allowed Marathon to dial into the bus to check for errors etc. I was just happy that Marathon did not throw away their refrigerator sized network analyzer for my vintage bus.

My understanding is that Marathon started using their own network design vs Techlon starting sometime in 200x.

[Deleted User]

Great explanation Gerald, I wasn’t even aware the Techlon system was considered multiplex. I think mine is still like yours, I do have the node relays scattered all over the bus. I like the way the system is designed with a fuse for each button circuit, the LED error light and push button to manually test the function. Marathon provided location drawings and placement of each node relay throughout the bus.

[Doug]

I agree Gerald, great explanation. Now, I know didley s%$# about electronic stuff, so in my case I just call my warranty guy in Kansas City.

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Mr. Iowa,

Your confused after spending too many hours in the air cond, sat radio equiped, air ride operator seat corn picker cruising around on your 5000 acre cash cow.

OMG …I’ll probably have some of your corn in my gas tank later this year.

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Al, looking out the window this morning……………I think my cow drowned…….

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Thanks Tom for the link. We installed 37 in less than an hour. My wife, son and I but I was the supervisor because someone had to drink the wine. No special tools needed other than a young strong pair of hands. I am not sure where you found 46 of these bulbs Tom?

The under sink lights (8) are different as well as the bay lights. Any idea where I can get those?

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Larry, H vs XLII, lots of interior differences. I have 10 just in the bedroom.