Community Forums

walt.0.meal · 03-22-2014, 09:22 AM

My air pressure fluctuates between 100 and 120 psi when driving. Pressure slowly decreases from 120 to 100, then goes back to 120 quickly. There is an audible alarm, but no warning lights. Air pressure is holding when engine is off.

Skip426 · 03-22-2014, 01:24 PM

The pressure 100 to 120, cycle, I would consider normal, air is used by the brakes, and suspension, and replaced by the compressor. The low air alarm , should not sound until the pressure drops to the 80>85 PSI range, then around 60 PSI the spring brakes on the rear axle will come on and stop the coach.
Personally , I think you have air pressure sensor; for the warning light; problem. Particularly if your gauge readings are correct.

Wizard · 03-23-2014, 06:52 AM

Mine, on the same coach as yours, does the same fluctuation as yours but my alarm sounds at about 60 PSI. At least that's where the alarm turns off when airing up.

johnzuki · 03-23-2014, 07:14 AM

Same coach, same fluctuation. Found a small leak in tubing running to rear suspension, air leaks down to 100, compressor kicks in, builds up to 120, compressor off, repeat cycle. Took about 45 seconds for air to bleed down from 120 to 100. Trace all your air lines, you have a small leak. As for the alarm, I agree, it should not sound until air is down to around 80. You may be hearing something else, the alarm and warning light operate from the same sensor as far as I can tell. Good luck finding your leak, took me about 4 hours of crawling and listening to locate mine. Best way is build up air, have suspension raised, shut off engine, and with coach on a concrete slab, crawl, look and listen.

walt.0.meal · 03-23-2014, 07:49 AM

Thanks for the comments. I did have an air leak on the black air line that runs from the rear on the passenger side to the front at the front connector. I replaced with a compression fitting and that fixed the problem with the pressure decreasing with the engine off. I also had no alarm until I left a rest stop on our last trip, and noticed the guage fluctuating. I will take my soap solution under the motorhome and check for more leaks. I am concerned that the air compressor may be going out.