Interlocks - A slightly different question

Twigg · 02-11-2018, 10:46 AM

Nope, I haven't pulled the wiring.

Yes, my bus still starts.

As I understand it, the usual interlocks should prevent the bus starting if the emergency doors are either locked, or open. The normal running condition being closed but unlocked.

Mine is behaving slightly differently, and I'm asking because I am at the point where I am removing all the wiring we will not need.

If I lock the emergency doors (A sliding bolt with a micro-switch), the buzzer(s) sound when I turn on the ignition. The same thing happens if I turn on the ignition with any of those doors open. So far, normal.

But here is the thing ... Neither condition prevents the engine starting, and it doesn't cut out when I select 1st gear.

That is ... the interlocks sound (loud) buzzers, but they do not seem to be tied to the ignition system.

Is this something people have come across before? It seems that I can simply remove all the switches, wiring and buzzers to no effect other than not getting warnings .... or I could leave it all in.

Rusty · 02-11-2018, 10:59 AM

Subscribed.

Iceni John · 02-11-2018, 11:45 AM

Was you bus originally a school bus or was it something else (a SPAB or a transit bus?) If it never was a school bus, maybe that's why you only have alarms and no interlocks? Mind you, my bus was a school bus, an it never had any interlocks, just some very strident alarms for the emergency door and window, so who knows? I guess the electrical schematic will tell you.

If your buzzers are only for an open door/window, why not keep them? It's not a bad thing to be reminded that something's open or unlocked before driving away.

John

Twigg · 02-11-2018, 12:08 PM

Quote:

Originally Posted by Iceni John

Was you bus originally a school bus or was it something else (a SPAB or a transit bus?) If it never was a school bus, maybe that's why you only have alarms and no interlocks? Mind you, my bus was a school bus, an it never had any interlocks, just some very strident alarms for the emergency door and window, so who knows? I guess the electrical schematic will tell you.

If your buzzers are only for an open door/window, why not keep them? It's not a bad thing to be reminded that something's open or unlocked before driving away.

John

It was owned by a school district and used as an activity bus. It is yellow, has all the warning lights and stop sign, but the stop sign was fixed closed (they didn't use it).

It was traded by the district against a newer bus, and I bought it from the dealer via auction.

I could keep them, but I don't want buzzers when the doors are locked, only when they are open. Shorting the micro-switches should accomplish that.

o1marc · 02-11-2018, 01:38 PM

Quote:

Originally Posted by Twigg

It was owned by a school district and used as an activity bus. It is yellow, has all the warning lights and stop sign, but the stop sign was fixed closed (they didn't use it).

It was traded by the district against a newer bus, and I bought it from the dealer via auction.

I could keep them, but I don't want buzzers when the doors are locked, only when they are open. Shorting the micro-switches should accomplish that.

Technically activity buses are not allowed to be painted yellow or have the flashing lights and stop signs. Only buses used to transport students to school and back daily are to be painted yellow.

Twigg · 02-11-2018, 01:42 PM

Quote:

Originally Posted by o1marc

Technically activity buses are not allowed to be painted yellow or have the flashing lights and stop signs. Only buses used to transport students to school and back daily are to be painted yellow.

This just isn't true.

Vehicles that transport students from home to school MUST comply with federal regs.

There is NOTHING to stop those same buses being used for activities. The only buses exempt from the color and lighting regs are those that were never intended to run routes.

We do it all the time. We also have three buses that are vinyl wrapped with school colors and logo that are only used for trips. The Band often travels in regular route buses, and we have spare buses that are fully compliant yet they only run trips.

Robin97396 · 02-11-2018, 01:54 PM

My first bus interlock system was as you described. I got my framing hammer and followed the sound until I found the buzzer then adjusted the noise level with the hammer with a few indelicate taps.

That half an interlock system confused me too. I agree, I don't like to travel with the doors unlocked.

o1marc · 02-11-2018, 02:02 PM

Quote:

Originally Posted by Twigg

This just isn't true.

Vehicles that transport students from home to school MUST comply with federal regs.

There is NOTHING to stop those same buses being used for activities. The only buses exempt from the color and lighting regs are those that were never intended to run routes.

We do it all the time. We also have three buses that are vinyl wrapped with school colors and logo that are only used for trips. The Band often travels in regular route buses, and we have spare buses that are fully compliant yet they only run trips.

So you agree with me. Then it's a school bus used for activities also. If it is being purchased as a MFSAB, it must meet federal regs. except for the control lights and stop bars and sign and paint.
Just because your school system does something does not mean it is legal.

Twigg · 02-11-2018, 02:18 PM

Quote:

Originally Posted by Robin97396

My first bus interlock system was as you described. I got my framing hammer and followed the sound until I found the buzzer then adjusted the noise level with the hammer with a few indelicate taps.

That half an interlock system confused me too. I agree, I don't like to travel with the doors unlocked.

Thanks Robin.

I think I'll re-wire to remove the switches on the locks, and leave the buzzers active on the "open door".

Either way, it looks like I am spared the "Help, my bus doesn't start and I don't know how to search the forum" post

Robin97396 · 02-11-2018, 02:47 PM

Steve, that is completely lacking the excitement of our usual interlock issues.

Twigg · 02-11-2018, 02:55 PM

Quote:

Originally Posted by Robin97396

Steve, that is completely lacking the excitement of our usual interlock issues.

You should talk to Mrs Twigg ... She shares your disappointment

Rusty · 02-11-2018, 02:57 PM

Quote:

Originally Posted by Robin97396

Steve, that is completely lacking the excitement of our usual interlock issues.

Unsubscribed.

roach711 · 02-11-2018, 06:56 PM

Quote:

Originally Posted by Robin97396

Steve, that is completely lacking the excitement of our usual interlock issues.

Yeah, what the heck? No drama, no panic, no angst. No stranded bus, no out of the blue no-start issue. Just a well reasoned approach to something that isn't even a problem yet.

Nothing to see here folks, move along, move along.

Twigg · 02-11-2018, 07:11 PM

Quote:

Originally Posted by roach711

Yeah, what the heck? No drama, no panic, no angst. No stranded bus, no out of the blue no-start issue. Just a well reasoned approach to something that isn't even a problem yet.

Nothing to see here folks, move along, move along.

Stick around. I'm bound to bugger something up, sooner or later

Genghis · 02-11-2018, 10:50 PM

I think there are two separate wiring systems, one for interlock and one for warning buzzer. See below the two schematics for my bus wiring 2001 Thomas.

Genghis sends.

z

EastCoastCB · 02-12-2018, 04:44 AM

Quote:

Originally Posted by Twigg

This just isn't true.

Vehicles that transport students from home to school MUST comply with federal regs.

There is NOTHING to stop those same buses being used for activities. The only buses exempt from the color and lighting regs are those that were never intended to run routes.

We do it all the time. We also have three buses that are vinyl wrapped with school colors and logo that are only used for trips. The Band often travels in regular route buses, and we have spare buses that are fully compliant yet they only run trips.

My 40 footer was an activity bus. Yellow.

Dapplecreek · 05-01-2018, 09:00 PM

Genghis,

I see on your schematic above that there are two buzzers for open emergency exits: one which would fire with the rear door, and one which appears to fire from all three. This 'all three' alarm is labeled "Switch Cabinet Alarm"...

My bus (a 2002 Thomas) has a sounding alarm in the corner electrical box (that is, the somewhat triangular switch box that is mounted at a 45 degree angle in the corner). The buzzer is cylindrical of two diameters (think a two-layer round birthday cake). Does that sound like this buzzer to you? If so, I may just unplug it...

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