Non-stop beeping coming from dashboard (2007 International 3300)

[u/Vegetable-Tea9074]

Hello, we have a 2007 International 3300 school bus, everything is fully operational on the bus (we have since replaced the alternator since recording this video, the voltage is now in the green). The only problem is this annoying beeping sound that buzzes every time the key is turned in the ignition and does not stop until the bus is shut off.

I have done some websurfing on this, and a lot of solutions stated this was an air brake alarm, but this bus uses hydraulic brakes, so it's not that. Additionally some said it was a "no child left behind" alarm, but the bus does not have that system installed.

The only thing that temporarily stopped the beeping was using a 'dashboard reset' trick I found in this video(https://www.youtube.com/watch?v=AOMvAko640Y), but this ONLY works if the key is in the first position (before the engine is turned on). Once the engine is running, the beeping does not stop even if I do this dashboard reset thing. The beeping ceases if the key is out of the ignition.

Important things to note before you respond (the beeping is still persisting despite the following):

• Since recording this video, the tank has been filled to half capacity
• The voltage is back in the green after replacing the alternator. All 3 batteries have been tested and are in great shape
• The warning lights on the dashboard in the video are "service (P)" and "brake pressure". Since this video, "service (P)" no longer appears on the dash, but "brake pressure" has remained.
  • We currently do not know why this is appearing on the dashboard, as we've recently entirely replaced the brakes and rotors and have no current issues with brakes. We currently think this could be the most likely reason for the beeping.
• The engine had it's coolant replaced and filled to the top
• The brake fluid has been completely filled
• The engine had a complete oil change and a new oil filter
• The bus runs perfectly fine with no engine issues. Accelerates great, no transmission issues.
• Before recording this video, we had initially thought it was an emergency exit alarm since "emergency exit" used to appear on the dash. Ever since we opened and closed every emergency exit however, this warning disappeared from the dash, but with no change to the beeping.
  • The two top emergency exit hatches are completely closed, not angled open.
• The loading door hydraulics still work, and the emergency latch being engaged or not makes no difference to the beeping.
• Every window is completely closed

So if anybody has any solutions, please comment below.

[u/Birby-Man]

This alarm is most likely related to the brake pressure light that is on. It's a critical function so a warning buzzer is pretty reasonable.

Either you didn't bleed the brakes properly after replacing... Idk? The "brakes". Or potentially damaged a wheel speed sensor which I'm unsure if equipped.

Most likely, need to bleed and inspect your brake system. Could be leaking as well.

[u/Haywoodja2]

You have an air parking brake as evidenced by the air parking brake knob on your dash. You have a low air pressure light on your dash and had a service parking brake light before. I'm going to guess you have low air pressure to your air parking brake system.

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[u/Single_Ad_5294]

Either you’re losing pressure somewhere (mechanical), or vehicle is not reading pressure accurately (electrical).

We can’t see your master cylinder, calipers, accumulators, SAHR canister?, or any of the brake lines running the length of the bus.

If you do find a leak and all your brake lines are in a similarly rusty condition, replace as much as you can muster in a day. Old lines like to spring new leaks once the weakest points are fixed.

[u/mwade2466 → u/Single_Ad_5294]

The bus has air brakes

[u/Single_Ad_5294 → u/mwade2466]

OP was talking about brake fluid. Where do you put that in an air system?

[u/wade2466 → u/Single_Ad_5294]

There is a park brake release button on the dash. Which would imply air parking brakes. That would be a pp-dc valve.

I haven’t seen air park brakes with hydraulic service brakes used except in the early to mid 90’s ford 550’s and gmc topkick c5500. I know of a few old ford L8000 that had it but they where late 70’s and early 80’s.

I stand corrected. I looked up some tech lit at work and international did/does make a chassis with air park brakes and hydraulic service brakes.

[u/ThisOldGuy1976]

All the answers seem to be lighting up you dash.

[u/Automatic-Salad-1638]

If the brake pressure light is on, you most likely have a leak in one of the brake hardlines. Are you able to get the pressure light to turn off with touching the brakes ?

[u/Browncoatinabox]

This is why air breaks is an endorsement on your license. Learn your break system inside and out, air systems are superior to hydraulic breaks in larger vehicles, but, if they fail...

[u/Aimless_Nobody]

Does the bus have a wheelchair lift? If "yes" then ensure the lift is stowed correctly, then turnn off (master) power to the lift. There should be a switch near the driver, the "release" parking brake.