Bus will start beeping constantly when warming glow plugs

[ourlittleyellowbussy]

So my bus is a 2007 Thomas built Freightliner 071PS FS65, with a Cat C-7 engine. It's got a wheelchair lift in the back too. And runs at 28 feet in length.
When I picked it up from Alabama it ran smoothly all the way to California, for reference that is roughly 2,000 miles and the trip was a total of 3 days.
Everything was fine when it got back to California and I even turned it on and ran it a few times after.
But recently when I turn the ignition to warm up the glow plugs, before starting the engine, a constant beeping noise will sound.
It's not any emergency exit as I have not touched any emergency exits and I have double checked them just in case. I even tried opening and closing the emergency back exit, and the emergency sound alarm is much stronger and louder than the other beeping alarm.
A new light came on the dash although, it seems to look like a red circle with a "Y" going through it. A red circle that looks like it has lines for ears and a line for a body looks a little something like this fella just the face is hollowed out, im really sorry if my explaining skills are awful.
All the glow plugs will still sound off and the bus will still start, any help is greatly appreciated!

 

[BamaBus]

Low air tank pressure? Check your air gauge reading and see if the pressure is low.

 

[ourlittleyellowbussy]

thank u i will be checking that today

 

[musigenesis]

If it's the low air-pressure alarm and it's beeping even though your air pressure is fine in both tanks, you might have a defective sensor. My bus had this problem and it drove me insane until I had it replaced - it was beeping about half the time even though my air pressure was always OK.

 

[slowstepper]

My 2009 International will beep after it starts until air pressure in the tanks gets to about 70 psi if I recall. Then it shuts off, I'm assuming thats NOT what you are experiencing.

I had a door warning beeping issue on my trip. it would just start up beeping indicating the door was open. I would be rolling down the hiway at 65 or 70, and it would start beeping. I'd stop - try several things, I'd get rolling again, all was good , till 3 or 4 miles down the road it would start up again. reclosing all the doors, nope, Shimming the switch activator - no luck, I tried unplugging the switches on the rear emergency door, no luck, also unplugged the sensor on the latch, no dice. eventually in desperation, after stopping every exit for 50 miles and trying stuff, i pulled the harness plug on the outside electrical panel, after trying to interpret the schematic. it did work, the alarm stopped, and no negative issues as far as I can tell, but I still wonder what the problem is/ was. The plug had apparently been pulled before by a PO.

 

[BamaBus]

If it's the low air-pressure alarm and it's beeping even though your air pressure is fine in both tanks, you might have a defective sensor. My bus had this problem and it drove me insane until I had it replaced - it was beeping about half the time even though my air pressure was always OK.

I think that's the case for a 92 Blue Bird I just picked up. However no mention of ever driving the bus or letting it run long enough to refill the tank.

What puzzles me is someone does research on a bus, comes all the way to Alabama, drives back to California and nothing here but a beeping. There has got to be a story somewhere!

 

[Simplicity-SKO]

My 2009 International will beep after it starts until air pressure in the tanks gets to about 70 psi if I recall. Then it shuts off, I'm assuming thats NOT what you are experiencing.

I had a door warning beeping issue on my trip. it would just start up beeping indicating the door was open. I would be rolling down the hiway at 65 or 70, and it would start beeping. I'd stop - try several things, I'd get rolling again, all was good , till 3 or 4 miles down the road it would start up again. reclosing all the doors, nope, Shimming the switch activator - no luck, I tried unplugging the switches on the rear emergency door, no luck, also unplugged the sensor on the latch, no dice. eventually in desperation, after stopping every exit for 50 miles and trying stuff, i pulled the harness plug on the outside electrical panel, after trying to interpret the schematic. it did work, the alarm stopped, and no negative issues as far as I can tell, but I still wonder what the problem is/ was. The plug had apparently been pulled before by a PO.

Which door?

If it was the service door, is it air, mechanically or electrically opened/closed?

 

[slowstepper]

Which door?

If it was the service door, is it air, mechanically or electrically opened/closed?

Hey Steve, I never figured out what door, I checked em all, couldn't make it stop, so i just pulled the wire harness, and the beeping stopped.
BUT
On my last leg home, the last 100 miles, the Pneumatic service door (I assume thats the one up front passengers load through?) kept flapping open and ignoring the open close switch, and messing with my mind. I have to try and figure that one out

 

[Simplicity-SKO]

Service doors have emergency switches/valves to release the door.

In a pneumatic, depending on the bus, there is usually a handle up towards the top of the service door area that you turn to seal the air lines.

On some buses, like mine, there's a switch around the drivers area.

Per pulling the harness....no Bueno. You want to know where the buzzing was coming from and why.

 

[ourlittleyellowbussy]

its air and it was just that the air gauge was low i just had to let it run for a couple mins

 

[Mason103]

Beeping Sound

Drove Public transit for 26 yrs from my experiences > not expert - I can be wrong so don't kill me.

Air Low / Due to leak ? in air line or air bags or some where / Not enough air in tank ? some takes a long time 5min or more on older buses .

 

[LargeMarge-TC]

If it will start beeping, that could be normal.
But if it will continue beeping, that could be abnormal.
.
If I was me, I would get it to stop.
.
.
These are a few, just some, of the amusing ways our bus buzzed with our heads [ !!! WARNING -- bullet-points approaching !!! ]:
* Seat belts?
* Chair lift?
* Doors latched in closed position?
* Luggage doors latched?
* Spare-tire in tight position?
* Headlights?
* All switches to 'off' during start?
* Operator weight in driver seat?
* Over-head destination announcements board active?
.
After about twenty minutes, we got tired of chasing.
We jerked the buzzer.
Your experience may be different...