Help with wheelchair lift wiring- bus won’t move

[Satoyama]

Hi everyone
I have a 2010 international maxx force 40 footer.
Last month I hastily removed my wheelchair lift and disconnected the wiring to the lil button that tells the bus when the handicap door is open. You guessed it- now my air brake won’t release so I’m sort of stuck in park. Plus, I discarded the button like a fool. But I have to remove it to build anyway.. So I need to know how to bypass or remove these wires successfully. Bypass interlock? Or maybe there’s another way.. Does the problem stem from the actual lift wire or the door indicator button?

HeLP! I’m a total electrical newbie.


The side with the WC lift has 6 wires that fed into the button. I have included a photo.
The other handicap door only had 1 wire and a ground.

Thanks
C

[msfitz]

Hey there! We are in the exact same situation! Did you get a solution? A $750 fine is heading our way if we do not move the bus by Tuesday!
Thanks

[Taz420]

I'm not 100% familiar with how exactly they work because my route bus does not have a lift to look at the plumbing, but my wild ass guess is there will be a solenoid valve somewhere under the hood connected between the supply air tanks (it might be a dual circuit valve or two separate ones) and the parking brake valve. When the interlock is engaged, the solenoid closes, cutting off supply air to the parking brake valve. Without supply air, it can't charge the spring brake chambers.

Now.. LOGICALLY, this solenoid would be "power close". That is, it closes when power is applied - otherwise it is held open by a spring. I can not for a second imagine that it would be "power open". where a loss of power would shut the valve causing it to dump your spring brakes unexpectedly. That being the case, if you can find that solenoid valve, you should be able to just disconnect its electrical harness and that should defeat the interlock.

If it is in fact a power open valve, then you'll have to go ahead and remove it from the air line.

Let us know what you find

[Truthseeker4449]

It actually could be both ways. My wheel chair equipped bus applies the service brakes with the wheelchair door open. I also have to hold down the brake pedal before the parking brake will release. That was fun to figure out when I first picked up the bus.

[Taz420]

Originally Posted by Truthseeker4449

It actually could be both ways. My wheel chair equipped bus applies the service brakes with the wheelchair door open. I also have to hold down the brake pedal before the parking brake will release. That was fun to figure out when I first picked up the bus.

Interesting... Does it also lock your spring brakes? Like will the button not stay pushed in?

I have a sports trip tomorrow afternoon so I won't be home until late but I can have a look at the lift buses after AM route and see what I can find and take some pics.

[Taz420]

Ok I had a look at the three lift buses that we have, two Blue Birds and a Thomas, and I didn't see anything under the hood that was spectacularly different than their non-lift counterparts. The interlock valves must be behind the dash.

[RjSibbett]

Does anyone have an update on this situation? I'm currently facing this myself and I have 3 days to get it figured out before I face a fine from the county, any help would be great. Same situation, I have a 06' IC RE200 35' Bus and I removed the handicap lift and all it's saftey wiring and interlocks and now my buses air parking brake wont release. I found an area under the front defroster that looks promising but I dont know enough about what I'm looking at to tell what I should do, like I said please any help is some help I have 3 days....

[Brewmaster]

Check your switches on your wheelchair doors. Usually there are two of them. one is for the wheel chair interlock, and the other is to lock the bus from moving. make sure they are both working. On Bluebirds and many shuttle buses they operate a shift interlock in the dash at the steering column to keep the unit either in park, or to keep the brakes on.

[RjSibbett]

I cut all those out not realizing it would keep me from releasing the parking brake. I handle the other interlocks unless it’s all the same because before the bus would just make a clicking sound and wouldn’t even try to start now it will just need to figure out how to release parking brake and bypass handicap door bs since it’s all been cut out

[Simplicity]

I drive bus with w/c lifts. Depending on the year, you'll have different safety mechanisms. The bus I drove today lets the engine keep running, the newer ones won't do that, and the really new ones you have to also flip a switch to activate power to the life.

Suggestions:

1) Since time is short and tomorrow is Friday, go ASAP to your local school transportation office where they fix the buses. Ask to talk to the transportation shop manager. Explain the situation and see if they can give you input. Don't wait, they go home early, especially on a Friday. Maybe you could pay one of the mechanics to take a look.

2) Research how to release air brakes for towing, how to bypass the interlock, etc.. Even if you don't find an exact answer, pulling bits and pieces of information can lead to a solution.

3) Get the schematic (I'll see if I have one) and determine which wire goes where and what they do. There may be one on the electrical panel door. If it's a full size bus, that should be located on the outside under the drivers window. Then, try and connect the wires to each other accordingly to simulate the switch being pushed in.

Use a test light to find the power wire, a meter to find continuity.

If you can't find a schematic, trace the wires using a device like this: https://www.amazon.com/Fluke-Network.../dp/B000FTADX0

4) Determine which is more expensive, the county fine or a tow. Pick the lesser of the two.

Best of luck.

[Rwnielsen]

I think you need to physically trace those wires forward and find where they added in. The chassis didn't have a wheelchair lift, it was added on. There is a control unit or relay set that is actively locking your brakes. That has to be bypassed or satisfied so it thinks all is good

[Brewmaster]

Okay, I'll most likely get shot for this but since I have no schematic on this bus, Here is the last choice you have to move it to safety. First, Check to see if the bus has the E-brake on the drive shaft, If it does, Disconnect the linkage. But chock the wheels first so the bus doesn't run over you. Second, If the bus uses the maxi brake chambers for a parking brake, Chock the wheels first, and cage the rear brake chambers with the tool mounted with them. Then drive off to a safe spot knowing you have no parking brakes. Chock the wheels when parks, release the maxi brake and hunt for your control air valve that is giving you crap. take out the valve..

Last resort to save you some money!

[Simplicity]

Have you tried searching for replacement switch so that you could maybe find installation instructions along with it?

Keep this simple. Those wires were attached to a switch. When that switch was in a certain position there were connections made or broken. If you can figure that out and simulate those make or break those connections, you might have your solution.

Best of luck

[Brewmaster]

If I were to have to guess in this case, I would say take the two wires that were on the one switch and connect them together. If I'm thinking correctly that should release your parking brake, If not, It will just light a light, or do nothing.

[Simplicity]

Watch this.

https://www.youtube.com/watch?v=6cU9boOTJS0

How to bypass the interlock system.

[Simplicity]

Check this out. PDF of Thomas bus. Section 1.5, interlock.

http://www.matthewsbuses.com/wp-cont...anual-2018.pdf

Did the switch you threw away look anything like these?

http://www.busparts.com/assets/pdf-f...s-door-pdf.pdf

Another related skoolie.net thread.

https://www.skoolie.net/forums/f10/k...new-10315.html

Another video, how to remove door alarm and still start bus.

https://www.youtube.com/watch?v=kovLFIr2Hq8

[Taz420]

I can offer a possibly relevant suggestion, but all of our fleet's RE's are Blue Birds. The only IC's we have are CE, and we only have one with a lift interlock that I can use for reference. It had been out for factory service when I first answered this thread (and I had just been hired), so I didn't even know we had it until it came back in November, and I honestly forgot about this.

But.. I'd imagine the interlock kit (because it is in fact an add-on kit, not factory equipment) is similar between the CE and FE/RE, just located differently. There will be three "extra" solenoids installed in the air system - one electric valve (on the firewall, two black lines and a harness to it) and two pneumatic relays (on top of the tray with three lines each). I went and took some pictures of what's in the CE.

After some intensive digging and wading through irrelevant diagrams, what it looks like is that the wheelchair door switch or interlock module grounds the electric solenoid to release the interlock. So what you need to do is (after you find the solenoid of course), is use a voltmeter on the solenoid leads. One will be hot with ignition on, the other must be cut and connected to a solid ground. Doing this will defeat the WC interlock, but still will not release the parking brake with the ignition off. To be able to do that, you must bypass the solenoid air circuit completely. I still don't know enough about air brake plumbing to tell you how to remove the whole thing, but I do know that the interlock is completely add-on kit, so it CAN be done. I think you'll be fine just bypassing it for now, at least to get you going.





Non-Interlocked CE bus for comparison.. The interlock has an extra orange and an extra green going through the firewall, so it's obviously not as simple as just removing the solenoid and relays and capping where they tie in. They have to tie into the parking brake valve or treadle valve in some way. That I can't help you with though, I don't think the boss would appreciate me pulling the dash apart in district buses

[ACoupleAdventurers]

Did you get this resolved? We’re having the same issue! Parking brake won’t disengage! Our is a 2010 International DT466