How often do HWH control units fail?

[obb_taurus]

I'm having issues with my rearmost air bags not inflating properly, I had my air system checked out and everything is good.  About 10 years ago my control unit needed to be replaced because the tag axle was not going to travel mode.  At the time, the shop that figured this out never told me what exactly that means but I'm wondering if it meant the rear airbags aren't inflating.  The control unit was sent off to HWH for fixing.  

Now I'm beginning to think this may be what's happening again so I was wondering if these control units from HWH fail easily or frequently?  Unfortunately I don't have great access to authorized HWH repair centers where I live so getting it checked is not that easy and I'm not sure if my coach is really safe to drive.  

Thanks

Mike B

01 Dynasty c/w tag

[vito.a]

The HWH control panel usually fails because water/moisture gets on it from the drivers window above.  

The rear air bags not filling is probably not the control panel.  If it was the control panel it would not fill more than just the two rear bags.  Its more than likely one of the many air solenoids or air lines in the system.  

It's very difficult to find a place that understands and is willing to work on the air ride system because it's so time consuming. 

I would start by driving the coach up on some stacked 2" x 12" boards so you can get under it safely and look for air leaks.  Many times it's a simple fix.  You can remove the air lines and cut 1/4" off and reinsert it to stop a lot of the leaks.  The air solenoids can be rebuilt with new o-rings fairly easily.     

[obb_taurus]

The funny thing is, if I use the control panel to add air to the back, they inflate with no problem, it is just when I dump the air and then let the system air up again, the back air bags don't inflate.

I don't think there is an air leak, as I mentioned, the air system was checked and no problems were found unless there is something that is related to HWH system that a shop which doesn't know the system might miss, also, I can leave my coach for weeks on end and it stays pretty well at the same level the whole time.

Honestly, not sure what to make of this problem.

BTW:  Didn't notice this before but I'm not talking about the control panel on the dash under the driver side window, I'm talking about the control unit or brain of the system.

[Nevada Rob]

When you say no inflating properly, what does that mean exactly? They don't inflate at all? Do they inflate some? Do you have a pressure gauge in the engine compartment?

[obb_taurus]

They pretty well stay flat.  If the air system is empty and is aired up, they remain the same as when the air was let out.  If I go to the control panel and add air to the rear, they will inflate so, yes, they do inflate but not on it's own. 

No, there isn't a pressure gauge in the engine compartment.

[Nevada Rob]

Do you have air leveling or hyd leveling? How do you adjust the air in the tag axle to balance the gross weight load?

[Ivan K]

I find it strange that you would not have a Mac valve and a gauge to regulate tag bags and down pressure. It should be in an accessible place for adjustment. Mine is on driver side rear of the motor.

[Nevada Rob]

Same here. Driver side next to the hydraulic filter. runs around 45-50 pounds.

[obb_taurus]

I have air leveling

Sorry, yes there is a gauge, I totally forgot about it, I will have to check that out.

Thanks for reminding me.

[obb_taurus]

Had a look and the pressure was set to about 33 so I increased it to 45 but it still didn't seem to have an impact.  The one difference was that the air bags weren't squashed like before, they lifted but they looked malformed and I don't think there was air in them.  I took some pictures which I'll post.

Also, I only have slides on one side and noticed that the clearance of the rear tires on one side is not as much as on the other, will attach pictures of that too.

[Guest Ray Davis]

Are you talking about the back will not come up for travel mode?    

Or will not level automatically,  only manually?

 

[obb_taurus]

If the reason the bags look the way they do means it's not come up for travel mode, then yes that's what I'm talking about.  Leveling seems to be fine.

Edited August 7, 2021 by obb_taurus

[Frank Bergamo]

Mike,

to properly set the tag pressure regulator you need to weigh all 3 axles. To much pressure on tag will overload front axle. To little, will overload rear drivers. Your axle weights will be on the placard, left and back of driver seat. Hope this helps.

 

[Ivan K]

45 psi should definitely seat the bags nicely. These just look stretched like if there was no air past the regulator.

[Nevada Rob]

I have read in more than one place that the best way to figure out the correct pressure on the tag axle for your coach is to weigh your rig fully loaded. Get each axle weight then divide the weight of each individual axle by the number of tires on said axle. Front axle by 2, drive axle by 4, tag by 2. Then try to do your best to balance the weight as even as possible with adding or subtracting pressure in the tag axle. Be sure to not overload the rated capacity of each axle. Since no two people carry the same amount of gear nor load the coach in the same way your rig will need to be set up for your circumstances. I pull a 26 ft. enclosed trailer with about 850 lbs. tongue weight. So my set up would be heavier in the rear than someone pulling a flat towed vehicle.

As far as getting your tab bags inflated, does it come up when you engage to tag lift for tight turns as an example? The air system is really not that complicated. Electric powered solenoids open and close a simple valves for each axle and side. I would recommend building some wood ramps from 2x8's or 2x10's stacked 4 high and long enough to get the drive and tag axle on the ramps. Put on some old clothes, gloves and safety glasses. Take a few bottle of soapy water (Dawn dish soap) a few rolls of heavy paper towels and start spraying and cleaning. You can trace your air lines, find air leaks and learn by putting your hands on these somewhat complicated machines.  

[planodp]

I tried to fix my and spend many day under the coach and inside the third bay. End up taking it to Foretravel Motorhome in July. This people really know the HWH system and have all the necessary parts to repair it. They also have 38 overnight parking space with 50 and 30 amps, with water and 8 full hook up for people getting they coach repair. While I was at Foretravel I had a great honor to meet Dave Pratt and his Foretravel IH45. What a awesome coach! I can only dream about owning one.

Let get back to the subject. Here is a link to all HWH Dealer and services Center for all state. https://www.hwhcorp.com/ml41023f2.html  

I would check each of the coil on the manifold. The coils should ohm to about 15.5 ohms (which can be easily checked by just unplugging the coil from the wire harness and inserting your multimeter test probes into the connector going to the coil. 

Attach is the troubleshooting from HWH. Good luck!

 

Level Sys Troubleshoting ml31043.pdf

[obb_taurus]

Thanks for the info on setting the pressure for the tags, thought I saw something in my manual about it but couldn't find a thing.

I actually haven't checked if the tag axle comes up, will do that next time I get out to my coach.  Since I had a shop check out my air system and they gave it a clean bill of health although they didn't know the HWH system so couldn't check that aspect.  I'm forced to think it has to be something with the control box, unfortunately I don't know if the same thing happened the last time my control box went, wish I would have asked the mechanic what the symptoms were of the tag axle not going to travel mode, maybe I have to contact HWH and see if based on the information they can tell me if this is a control box issue.