Airbags not inflating?

[Rustymayes]

After my last trip, while I was placing blocks under the jack system, I noticed a pretty large air leak sound that had not been prominent in the past. Today I decided to look into it so I raised the coach up a bit higher with the jacks leaving the wheels on the ground. I started the engine to pump up the system and it took very little time for the pressure to build up what is about 135 on the gauges before the relief blows. I shut down the engine to listen for leaks but oddly, I could not hear even the faintest of hissing. I then lowered the coach and dumped the air with the manual dump button on the jack control pad, fired up the engine and waited for the coach to lift to ride height on the air bags. The pressure built up in the system and both guages read 135 but the coach did not lift at all. I am wondering if a solenoid somewhere is inoperative. I cant drive the coach like this for sure. I did notice that last trip on Friday, I stopped after a 60 mile drive, stopped for about an hour and then went to move the coach to reposition on the property and the suspension was bottoming like the airbags were flat. After about five minutes they raised enough to not bottom any and I parked and leveled the coach for and overnight stay. In the morning I started the coach and went about my normal routine in stowing the jacks and retracting the slides with no issues. On the drive home though I noticed that my guages were not reading the same air pressure. One was about 10 to 15 shy of the other. I could not remember if they typically read 150 or just shy but I always thought they were about the same. Any insight would be appreciated.
Thanks
Rusty

 

[Neal]

I would reach out to whichever chassis vendor you have. If on the road and you have service such as with coach-net you may want to get someone out to take a look. I'm not sure that's a drivable condition. Could be a shuttle valve stuck, air line issue, who knows, not an expert but I don't think driving with air bags not inflated is a good thing to do.

 

[Rich W.]

That’s an interesting situation and not my speciality but I’m watching this to see what I learn. Definitely can’t drive it far that way. Where are you stuck? Also what chassis and leveling system do you have?

 

[Rustycoach]

I am at home and I have freightliner chassis. I actually cycled the park brake with the coach in gear and that triggered the bags to inflate but quick. I still have a leak which gets bigger with the coach on the leveler jacks. I still need to track it down.

 

[Neemer]

When you manually deflate as I often do, you can cause the bags to reinflate by hitting the auto store button.

I had something weird happen last week as well. I was airing up and I heard what sounded like a jacks down alarm, except it was external and underneath the front of the coach. Then I heard something pop off and the bags stopped inflating. I hate those little heart fluttering moments.

Anyway, I went inside and hit the auto store button again and the bags continued to inflate. It hasn’t happened again. One of those weird mysteries.

 

[NWIP]

Yes there is a sequencing logic (valve) for the HWH jacks that gets out of whack, generally if you manually dump and level individually (no auto). It can be reset by hitting auto level and then auto store once jacks start to extend, coach should then air up normally.

@Neemer I’ve never heard an alarm outside the coach but I have had the bags suddenly pop while inflating. I just figured it was the bag settling inside the spring

 

[RKins]

I had that issue once and it ended up all I needed to do was press the Auto level button. It works with the air solenoid to dump the air and closes the air solenoid so the system can air up when you start the coach. I think I got into that problem by playing around with the manual dump button, which opens the air solenoid but didn't close it.
Edit: I see NWIP and I were typing at the same time.

 

[NWIP]

Great minds think alike @RKins

 

[Rustycoach]

Come to think of it, I had stored the jacks with the down buttons since I had manually lifted to coach rather than use the auto level function. So that is why the bags did not inflate automatically. Still need to see about the leak .

 

[JRS]

Had a situation 1.5 yrs ago where I was manually lifting coach with the jacks and it suddenly stopped working. When leaving the RV Park, just manually relieved the pressure to raise the jacks. Brought in the slides and started up. Air bags wouldn't inflate. Ended up being a burnt out fuse housing with the wiring near my hydraulic pump. Replaced with a much larger fuse housing and fuse (if same amps). All has been well since....

 

[GUS2000]

What was the final outcome of this one?? enquiring minds want to know

 

[Rustycoach]

I never looked into it once I knew the source. It seems to be intermittent and has never failed to adjust to ride height.

 

[SteveMA]

Had a total Electronic Ride Height (ERH) rear leveling system failure about 3 weeks ago on our 2020 Mountain Aire with Valid air leveling. Happened when I was coming off the freeway and turning at the traffic light - Valid FAULT alarm went off with an error code of "no communication to Rear Control Module". Once I put the HWH jacks down (and dumped the airbags) I was dead in the water as the airbags would not refill for any reason. Spoke to Valid, did a bunch of tests and a hint they gave me solved the issue (at least I can air up the suspension) - They said "failure rate on the ERH controllers is near zero - check the voltage at the connector on the ERH Controller plug..."

Result and fix - Rear Freightliner PDM failure for the 2nd time (Eaton PDM) - Our PDM was replaced when the TOAD lights and AC clutch became intermittent about 18 months ago. When I discovered there was no +12V on the line that powers the Valid Rear Control Module for the ERH system at the connector to the Rear Control Module and then also confirmed no +12v at the connector at the PDM, I did a temp 12v connection to the wire that supplies +12V to the Rear Control Module and ... the system came right back to life. Installed an inline fuse for now with power to the ERH controller and all good.

In my research I found that the fuse for the rear ERH was good, and showed +12V on both sides, also replaced the fuse for certainty, however from there it did not get to the connector and into the wiring harness up to the ERH. The fuse is directly above the area of the PDM that failed due to micro cracks in the solder/PCB for the Toad lights AC clutch etc, which makes it highly likely it is a related failure (like 98%) - this will turn out to be a crack in the PCB of the PDM (again).

I have now heard about multiple cases where the replacement PDM has failed - a 2nd and even 3rd time. I am reaching out to FCCC service to start the process...

May not be related to your issue, but I suspect the failure on our coach will not be the only or last one.

 

[GUS2000]

Well our rear airbags didnt want to inflate this week when we were going to leave Orange Beach and it turns out one of the bags has a leak.. got the part overnighted from Freightliner and waiting for the mechanic to show up to install it..

 

[GUS2000]

Update on the airbag.. appears that the original airbag was not aligned properly when it was installed by Freightliner on the chassis which caused it to compress in a way that damaged the internal components of the airbag. waiting on feedback from Freightliner..