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HWH Control Box replacement options??

April 30, 2019, 05:52:27 pm

Preamble: 1993 Grandvilla - stored for two weeks, up on blocks ( have an air leak somewhere and did not want settling and torquing). House batteries were disconnected while we were away in England.
Start up today - rear bags inflated and lifted - front bags remain soft.
'Travel' light on control panel is NOT lit.
Red 'On' light is NOT lit when the key is on. Double click will not activate leveling.
I opened up the panel and assured that the connection was good. Did a system reset, but no effect.
Checked the HWH Service Manual and System Text Book and as soon as I started to work my way through the trouble-shooting sequences, it was clear that I had to dive into the Control Box in the cargo hold.
Power from battery was 13VDC.
With ignition switch on, the power from the ignition solenoid was 13VDC.
The verdict from the trouble-shooting manual (since there is power to the Control Box) (all connections are good and all fuses are unaffected and whole) - is that I need to replace the Control Box.
Now comes the fun part of finding the thing. The existing Control Box according to the label is part number AP9488 / SN 257.
Local RV dealer says that none of his suppliers have such a thing (outdated?) but he found some in an on-line search. Beam site tells me that a replacement is RAP90026 for the 600 series (9"X 14" box). So the search is on...!!
I need advice regarding any steps missed in my diagnostic sequence.
I also, I suspect, need to find a source for either an AP9488 (is used okay?) or for the RAP90026
I am on the West Coast of Canada, although not far from possible parts sources in Northern Washington State.
Should I search anywhere other than HWH?
The HWH website has this discouraging comment, "Replacements new or re-manufactured units are no longer available. HWH might be able to repair your existing unit"
Advice is welcome.

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Re: HWH Control Box replacement options??

Reply #1 – April 30, 2019, 06:00:56 pm

Why not contact HWH directly? They recently milled a new 6 pack manifold for my '93 U300.

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Re: HWH Control Box replacement options??

Reply #2 – April 30, 2019, 06:04:33 pm

I have a 96 U270 that the HWH box died 4 years ago.  I have been working around its deficiencies and problems since then.  My Travel light does not shine, but the Travel mode works going down the road.  When parked the system does whatever it wants.  Usually the front end goes full up in 20 minutes.  So I must "babysit" the thing until it runs out of air.  I find this a good excuse for a beer.  Other than my habit of tapping any accessible object with the heavy end of a screwdriver, you have done all the same things to the box that I have.  Have you checked that the air valves are getting a signal?  Good luck.  (If I ever get to Iowa, I might try the factory folks there to look at my museum piece.....)

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Re: HWH Control Box replacement options??

Reply #3 – April 30, 2019, 06:52:24 pm

I would call HWH and see if they can repair it.  They did my '99 back in December for $75.00

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Re: HWH Control Box replacement options??

Reply #4 – May 13, 2019, 11:25:15 pm

So... the saga continues. I sent both the Control Box and the Touch Pad to HWH, and they were terrific, with a three day turnaround. seems like they replaced a relay and a switch, and put on a new cover on the Touch Pad.
After installing it today I started up - hoping big time that I would see the Travel light show up to signify that the system was once again functional. It was not to be!!!
The current symptoms (beside there being absolutely no air in the front bags) is that the rear bags are feeling very firm (perhaps harder than I have ever felt them to be). Steel blocks are separating the upper and lower frames so the unit remains level sitting in its storage spot.
I did an inspection on some of the wires at the front six-pack. Each of the Travel solenoids clicked when I pulled apart the waterproof wire connectors - so I believe they are receiving a signal.
One of the wires of a Lift solenoid pulled out of the back of one of the water-tight connectors - so i thought i had found the problem, BUT when i made what i thought was a good connection - nothing changed!
I now have a replacement water-tight connector and will install it in the morning.
Question: is there a way to determine if there is continuity in the wires of the front wiring harness, from the Control Box to the six-pack? On a individual wire-to-wire basis?
Q: since the rear bags seem unusually firm and pressurized, might there be an issue with the overall system pressure switch at the rear six-pack? ( I have replaced the pressure switches on the front six-pack, one at a time, over the past year - assuming that they were implicated in some inconsistent leveling). Note: throughout much of the past 7 months, I have had the upper frame supported by steel blocks so that I could just shut off the leveling system, rather than worry about it leading to torquing the frame through uneven leveling. A month ago, I drove the unit for about half an hour moving it from one camping spot into a storage spot (and there was no problem). I then blocked it up and went to England for two weeks. Upon our return, the Travel light on the Touch Pad would not light and the front bags would not fill.
My first line of inspection is to ensure that the wires to the solenoids are all functional. Any suggestions as to how to do this, will be appreciated.
Q: might there be an issue with the front leveling valve sending/not sending a signal (since the unit is blocked up and the valve might be stuck in an up position??
Floundering here so need suggestions from the fabulous Forum.

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Re: HWH Control Box replacement options??

Reply #5 – May 14, 2019, 06:21:57 am

A quick and easy way to see if a solenoid is energized is to hold a screwdriver tip or big nail to the back of the coil.  If it sticks the solenoid is energized.  The coil is an electro-magnet.
Good luck

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Re: HWH Control Box replacement options??

Reply #6 – May 14, 2019, 07:03:36 am

Woody,

Sounds like you still have 2 problems so here are some thoughts.

The rear pressure switch could be bad or it's  wiring as this is what sends a signal to the travel light.

While you were checking the front 6 pack did you inspect the ride height valve's linkage? The ride height valve ( I think you are referring to as a front leveling valve) is totally manual as it has no electrical wiring connected to it.  All it knows is to add air or release air due to the possession of the internal shuttle valve that is controlled with the linkage that connects to the frame. If the travel solenoids are opening then the air goes to the ride height valve before being fed to the air bags.

Can you push the raise button (on the push pad) for the front and the front respond? Like you are manually raising the coach to add/remove frame blocks

Mike

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Re: HWH Control Box replacement options??

Reply #7 – May 14, 2019, 08:32:18 am

Also, a better check of rear bags is to measure RIDE HEIGHT-- more accurate than feeling for pressure.

And, as Mike mentioned,  I would suggest doing a quick ride height check both front and back (yes, with safety stands removed). In travel mode, the system is entirely mechanical. Two ride height valves in back, one in front.

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Re: HWH Control Box replacement options??

Reply #8 – May 14, 2019, 09:09:57 am

Woody,

If you have safety blocks in place, and start the engine, the HWH system will try to bring the coach to "ride height".  If it thinks the coach is sitting above ride height,  it will exhaust air from the bags as it tries to lower the coach.  To get a true sense of how the system is performing, you must remove the safety blocks, then let the HWH system do its thing.

If, as you describe, the front bags are empty, but the rear bags are inflated (hard) then that could indicate a problem with the "lower" solenoid valves on the rear 6-pack - either not working, or not getting a signal to open, or the exhaust ports are blocked (mud daubers?).

The (80 psi) pressure switch on the rear 6-pack manifold does not control air pressure in any way.  All it does is sense the system air pressure, and report the pressure reading to the HWH brain box.  If the rear pressure switch is happy with system air pressure, the TRAVEL light on the control panel will be on.  This does not mean the coach is at travel height, and does not mean all the other components are working correctly.  It only means you have sufficient system air pressure to support the system operation.

Strongly recommend you follow the logical trouble shooting steps in the HWH manual linked below (ignore the "tag axle" info):

https://www.hwhcorp.com/ml11148.pdf

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Re: HWH Control Box replacement options??

Reply #9 – May 14, 2019, 09:52:33 am

Also there are check valves in the front 6 pack which can become stuck and not let air into the 6 pack manifold. They are on the sides of the manifold under a hexagon nut. If you hit the raise for the front and you don't get air into the bags they could be the cause and also there is a pressure regulator for the front air bags that could be bad not letting any air to the manifold.

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