C2 Saf-T-Liner Multiplex - Best approach?

TheMacyFamily · 08-12-2020, 10:23 PM

I bought a Thomas 2013 C2 Saf-T-Liner and I'm currently doing some demo and just now stumbled upon the complex multiplex system.

After doing some research, it looks like this complicated electrical system keeps people away from converting them! No turning back now though, I'm in it to win it. What do you think the best approach is? I'm thinking I need to leave as much of it intact as possible and hope nothing goes wrong with it and build out a separate system for everything else with the conversion and do my best not to mess with it.

That is unless you guys have a different option!

TJones · 08-13-2020, 12:43 AM

You are on the right track with leaving the wiring alone. There are enough people that "brick" thier bus after cutting the wrong wire and not being able to start the engine. If you do want to make wiring modifications make only one change at a time and test to see if the bus still starts and drives. You should be able to pull up a wiring diagram for you bus from the internet.

Ted

joeblack5 · 08-13-2020, 06:59 AM

What brand, kind multiplex system do you have? Some pictures would help..how does your interface module look..we have a multiplex system in Dory and it takes time to get used to.

cadillackid · 08-13-2020, 07:33 AM

the earlier Thomas system works on having different resistances for each dash switch that the computer recognizes as an accessory.. its important not to chaffe the harnesses or cut and improperly splice it.. the computer knows by the voltage it gets returned on the harness which switch you have operated..

drivers Leaving the driver-window open in the rain contributed to quite a few corrosion issues whiuch change resistances of the switches when they dont make good contact... and that makes things go no-worky.

TheMacyFamily · 08-13-2020, 08:19 AM

Thats one of the first things I noticed, that they put a lot of it right under that big window!

PlaynDanger · 08-15-2020, 08:22 PM

Almost all the safety systems with the C2 are a simple open to ground switch so the rear door, emergency exit windows, roof top escape hatch and bus door switches can all be taken out no problem. any and all lights can be removed with no issues, After that I would build a separate 12 and 110 volt systems from the bus to power everything from auxiliary batteries and shore power or inverter. If you do remove anything like the above post said cut one wire at a time and check systems as you go.

TheMacyFamily · 08-16-2020, 07:27 PM

Quote:

Originally Posted by PlaynDanger

Almost all the safety systems with the C2 are a simple open to ground switch so the rear door, emergency exit windows, roof top escape hatch and bus door switches can all be taken out no problem. any and all lights can be removed with no issues, After that I would build a separate 12 and 110 volt systems from the bus to power everything from auxiliary batteries and shore power or inverter. If you do remove anything like the above post said cut one wire at a time and check systems as you go.

Thanks for the help!

I've taken out some lights and speakers, but I'm looking at taking out the Acs and the heaters

BirdietheBus · 02-12-2021, 10:37 PM

Hi! Any updates on how you’ve handled the multiplex? I just bought a 2009 Saf-T-Liner C2 and am trying to figure out how to tackle or avoid this!? Any advice?

mblasius · 05-14-2021, 12:14 PM

Hey all,

Very happy to see that I'm not the only one with this issue, and I'm hoping someone here has had resolution.

I too stumbled upon the multiplex wiring after expecting the more traditional wiring and Vandalock work-arounds provided by others. I have a 2013 Freightliner with 6.7L Cummins and a white, Thomas-built Saf-t-liner C2 body. So far I have removed all the windows and the lock on the rear emergency door, which has obviously disabled the bus. Turning the ignition turns the engine but does not fire. I have a few questions for the group...

1. Has anyone successfully disabled this system? I'm thinking now that the easy solution is to leave it in tack and complete the circuits so the bus thinks everything is normal.

How do I know if I have the Vandalock system or if I've just tripped the ignition sequence by removing safety features?

2. Does anyone know which parts of the bus disable ignition besides the emergency door? I assume the emergency windows. What about the main door (I intend to remove this).

3. Has anyone purchased/downloaded/used the DiagnosticLink software meant for these specific buses to work with electronics? https://diagnosticlink.nexiq.com/DTN...istration.aspx

I appreciate any time and information you all can supply.

Thanks!

Michael
The BlasiuBus

08freightliner · 05-19-2021, 08:59 AM

i have an early c2 and no issues at all with back door or emergency stuff unplugged. there may be a fuse for all that stuff that was removed before i got bus. Otherwise the multiplex is kind of nice in terms of adding stuff just pop the right switch in and it shares the same stuff as freightliner. so if you need a switch easy to locate.

sereedy2 · 02-09-2022, 06:33 PM

Hi guys!! My wife and I have officially joined the club, we can't start our bus and it's definitely because we tripped the safety features of the bus. This is a 2007 Thomas C2 that runs on the multiplex electrical system.

Up until today, we thought we were doing things correctly. We removed the wheelchair lift and the No Child Left Behind button in the back of the bus that you need to press after you shut off the bus, assuming you've engaged the hazard lights and stop sign that a driver would when dropping off a child.

After removing each of these, we made sure the bus would start before we cut the wires or threw anything out. What we had not done at any point until now, was engage the "Dropping Off a Kid" switches (hazards and stop sign). Now that we played with those, the bus won't start.

We tied the two wires together that were attached to the Child Button, but no go. Then we found the button that we thought we had thrown out!!! We tied both wires as they had been originally, but no go. WTH?

We made sure everything was closed properly and that the locks were set correctly. We double-checked the windows and ceiling hatches.

Could this have something to do with the wheelchair lift? I haven't seen anything suggesting that engaging the "Kid Drop Off" switches has anything to do with the wheelchair lift.

We're getting what I assume is an error code on the dash 3_2.2 and another that says BH 16.4 which I have seen in another forum means that there is a missing switch. We have never messed with the switches, and I've also seen this message before but I honestly cannot remember what caused it.

Any ideas on what we can do? I've read a bit about running one of the wires to ground, but I'm not sure which wire, how to do that, if I need to do that with just the Child Button, the WC wiring, or both.

PLEASE HELP & thank you to all of you for asking great questions and sharing your wisdom!

Vermonster · 10-06-2023, 09:44 PM

Quote:

Originally Posted by sereedy2

Hi guys!! My wife and I have officially joined the club, we can't start our bus and it's definitely because we tripped the safety features of the bus. This is a 2007 Thomas C2 that runs on the multiplex electrical system.

Up until today, we thought we were doing things correctly. We removed the wheelchair lift and the No Child Left Behind button in the back of the bus that you need to press after you shut off the bus, assuming you've engaged the hazard lights and stop sign that a driver would when dropping off a child.

After removing each of these, we made sure the bus would start before we cut the wires or threw anything out. What we had not done at any point until now, was engage the "Dropping Off a Kid" switches (hazards and stop sign). Now that we played with those, the bus won't start.

We tied the two wires together that were attached to the Child Button, but no go. Then we found the button that we thought we had thrown out!!! We tied both wires as they had been originally, but no go. WTH?

We made sure everything was closed properly and that the locks were set correctly. We double-checked the windows and ceiling hatches.

Could this have something to do with the wheelchair lift? I haven't seen anything suggesting that engaging the "Kid Drop Off" switches has anything to do with the wheelchair lift.

We're getting what I assume is an error code on the dash 3_2.2 and another that says BH 16.4 which I have seen in another forum means that there is a missing switch. We have never messed with the switches, and I've also seen this message before but I honestly cannot remember what caused it.

Any ideas on what we can do? I've read a bit about running one of the wires to ground, but I'm not sure which wire, how to do that, if I need to do that with just the Child Button, the WC wiring, or both.

PLEASE HELP & thank you to all of you for asking great questions and sharing your wisdom!

Did you ever get this figured out?

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