Diesel motorhome

Sounds like air leaking. You could turn key off and let engine stop then turn key back on don’t start engine see if you hear air leaking. You can do the same thing and push parking brake in. Then apply the brakes and see if you hear air leaking

 

Does dash air gauge drop when the light flickers? That would support the leak theory.

Could be a simple check valve or a leaking hose. Either way not something to ignore. Get it fixed

 

Do a break test as required by FMCSA to determine how bad your leak is. Then charge up the system to at least 110psi. Shut the vehicle off and check all air lines and their connections by spraying soapy water on their surfaces. If you see bubbles growing you have a leak.

 

I recommend you fix that 'break' light, learn what an air dryer sounds like and get some help from someone IN PERSON who knows how an air-brake vehicle works and can show you. It's likely these things don't have anything to do with one another.

 

Can you verify the park brake light is low air pressure, brake drag warning, or at least verify the air pressure in primary/secondary reservoirs during the occurance?

The air chuffing could just be your regulated pop-off valve at the air drier.

Here's the troubleshooting (TS) I recommend doing, and you don't have to be a mechanic to do it.
1: park in a flat area, apply wheel chocks, and maybe grab a helper.
2: drain the air with the foot brake pedal until it's down to 0 psi in both reservoirs.
3: start the unit and record the amount of time it takes to build from 0-100 psi with engine at idle or 1,000 rpm. - if this is taking around 2 minutes or more then you probably have a damaged line from your compressor to your drier, an underperforming compressor, or a restriction to the air compressor suction/inlet hose.
4: continue to build air until governed pop-off; 115-145 psi in both reservoirs. - if outside of the specifications you might need to A) adjust your air governor, B) R/R air governor, C) inspect Pressure Relief Valve on drier.
5: get out and inspect the entire unit for signs of leaks. - repair leaks as necessary.
6: KOEO (key on engine off) release your park brake and inspect the tnire unit for signs of leaks - repair as necessary.
7: have a second person apply the foot brake to the floor and inspect around all wheel positions for service air leaks - repair as necessary.

You can use these 7 steps to diagnose nearly every leak on any CMV with air brakes. SOMETIMES it can be something pushing air out of it and it's actually a sign of an upstream/downstream failure due to that other component bypassing (it's broke internally). There's an easy way to test that on youtube, and here is the link provided.



Hope this all helps.