Pressure switches on front sixbag/bags

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Pressure switches on front sixbag/bags

January 29, 2022, 08:26:28 pm

Could a faulty pressure switch on the front six pack prevent one corner from raising? I thought the front was one "circuit", but after reading the HWH manual it sounds like each corner has it's own pressure switch.

Current symptoms: I put coach in "raise" mode, three corners go up. Front right corner gets NO air at all.

If I then hit "dump", the front left corner will not dump. This makes sense to me after reading the HWH leveling system manual.

Quote

The front air pressure switches on all 600 and 680 Series
Leveling Systems are used during any lower functions,
manual operation, automatic operation or use of the "DUMP"
button. When the pressure switch for a front bag turns on, it
sends a ground signal to the control box. This will inhibit the
opposite side front air bags from lowering.
EXAMPLE: While pushing the right side lower button, the right
front air pressure switch sees low air pressure. The front lower button is then pushed. The right front lower solenoid valve
will turn on and open, but the left front lower solenoid valve
will not turn on. The left front bag will not lower. This is done
to prevent the front of the vehicle from twisting. If one side
of the front of the vehicle is as low as it can go, lowering the
other side will twist the vehicle

If I put the coach in travel mode all 4 corners go to ride height. Once they're all at ride height I'm able to dump all the air from each corner.

EDIT: further reading makes me think there is a raise solenoid for each corner (see pics). Correct?

Re: Pressure switches on front sixbag/bags

Reply #1 – January 29, 2022, 09:52:49 pm

Quote from: Elliott – January 29, 2022, 08:26:28 pm

1. Could a faulty pressure switch on the front six pack prevent one corner from raising?
2. EDIT: further reading makes me think there is a raise solenoid for each corner (see pics). Correct?

1 No
2,Yes

Mike

Re: Pressure switches on front sixbag/bags

Reply #2 – January 30, 2022, 06:58:07 am

Elliott,

The ride height works off a separate set of solenoids than the raise function. Pull the coil off the right front raise solenoid and check to see if it is burnt up (check with an ohm meter) While you have the coil off check to see if you are getting a voltage through/to the plug on the solenoid by having someone else push the raise button while you check.

Mike

Re: Pressure switches on front sixbag/bags

Reply #3 – January 30, 2022, 09:46:51 am

Quote from: Pamela & Mike – January 30, 2022, 06:58:07 am

Elliott,

The ride height works off a separate set of solenoids than the raise function. Pull the coil off the right front raise solenoid and check to see if it is burnt up (check with an ohm meter) While you have the coil off check to see if you are getting a voltage through/to the plug on the solenoid by having someone else push the raise button while you check.

Mike

Thanks Mike, is there a way to conclusively identify the front right corner's raise solenoid once I'm under there? The diagram I shared above seems to imply it is one of the bottom ones.

If not, I suppose I can identify the front left corner's solenoid since I know it works and assume the front right is the opposite one.

Re: Pressure switches on front sixbag/bags

Reply #4 – January 30, 2022, 10:06:19 am

Refer to your air system diagram. Each air line has a unique ID label. Only one air line goes to RF raise solenoid on 6-pack manifold.

Re: Pressure switches on front sixbag/bags

Reply #5 – January 30, 2022, 10:21:59 am

Elliott, for clarity:

Ride Height (driving position): Single front valve to control coach level front to back. Dual rear valves to control coach side to side (there are 3 valves).

HWH Level (parked position): Pair of air bags in EACH corner are controlled by their own valve (there are 4 valves). Each valve is always joined with another valve to raise and lower. For example: 2-front joined to raise & lower front, 2-side valves joined to raise & lower that side. So, any one valve will be alternately joined to another valve to level coach while parked.

The two air bags for each tire position are always tied together and cannot be individually controlled.

Your information about how HWH uses front pressure switches was a surprise. Thanks for the documentation.

Re: Pressure switches on front sixbag/bags

Reply #6 – January 30, 2022, 11:19:22 am

On my coach, air line #36 is the RF "raise" supply line going from the manifold to the right front corner air bags. Looking at the manifold from the side where the air lines connect, it is in the bottom left corner. I marked my manifold for the air line positions when I rebuilt my solenoid valves. See photo:

Re: Pressure switches on front sixbag/bags

Reply #7 – January 30, 2022, 11:24:01 am

Quote from: Chuck & Jeannie – January 30, 2022, 10:06:19 am

Refer to your air system diagram. Each air line has a unique ID label. Only one air line goes to RF raise solenoid on 6-pack manifold.

This is where some of my confusion is. That diagram indicates two lines coming off the manifold (one for each bag). The locations that those two airlines enter the manifold don't physically correlate to a solenoid.

So it seems line #36 controls the bag in front of the right steer wheel and line #35 controls the bag behind the right steer wheel? Am I interpreting it correctly? But it's a single raise solenoid on the manifold that controls both lines?

Re: Pressure switches on front sixbag/bags

Reply #8 – January 30, 2022, 11:30:54 am

The diagram is not a exact depiction of the actual physical air hoses. It just shows how each corner is controlled.

Looking on the other side of the manifold, where the solenoids are mounted, the bottom right solenoid should control air line #36.

You would need to follow each air line by hand from the manifold to see how it actually connects to the air bags. I have never tried to do that.

As long as everything works on my coach (which it does) I'm happy.

Re: Pressure switches on front sixbag/bags

Reply #9 – January 30, 2022, 11:34:18 am

Quote from: Chuck & Jeannie – January 30, 2022, 11:30:54 am

The diagram is not a exact depiction of the actual physical air hoses. It just shows how each corner is controlled.

Thanks Chuck

Re: Pressure switches on front sixbag/bags

Reply #10 – January 30, 2022, 11:37:09 am

If you want to try a simple test while you are under the coach, just swap the coils on the two bottom solenoid valves.

If your problem moves to the other corner, then you know you have a bad coil or wiring harness connection (or blown fuse in control box).

PS: Don't forget to put both coils back in the proper position.

Re: Pressure switches on front sixbag/bags

Reply #11 – January 30, 2022, 12:00:35 pm

Have you checked the fuses in the control box? If you have the 600 Series leveling system, fuse #2 is power to the RF raise solenoid.

Re: Pressure switches on front sixbag/bags

Reply #12 – January 30, 2022, 01:21:33 pm

Elliott,

The thing that is confusing you is that you can't see the air gallies that are drilled internally in the manifold that connects 35 and 36 in that print that you posted.

Mike

Re: Pressure switches on front sixbag/bags

Reply #13 – January 30, 2022, 01:37:30 pm

Quote from: Chuck & Jeannie – January 30, 2022, 12:00:35 pm

Have you checked the fuses in the control box? If you have the 600 Series leveling system, fuse #2 is power to the RF raise solenoid.

That's in the silver HWH box right? (pic attached)

I don't see that combination and configuration of fuses. I do see eight 5amp fuses all evenly spaced behind one of the circuit boards but not the 10am or 7.5amp fuses

Re: Pressure switches on front sixbag/bags

Reply #14 – January 30, 2022, 02:03:48 pm

Not a 600 Series box - totally different.

Look on the underside of the lid for a list of circuit breakers or fuses.

If not there, you'll have to find the manual for your HWH 680 Series system.

https://www.hwhcorp.com/ml17140.pdf

Search for HWH AP18508 turned up:

https://www.hwhcorp.com/mr156600.pdf

Re: Pressure switches on front sixbag/bags

Reply #15 – January 30, 2022, 02:51:39 pm

Found the issue. No continuity in the #36 solenoid. Thanks guys, you saved me a fair bit of troubleshooting once again.

On a semi-related note, I noticed this little tag on the solenoid labeled "raise". This once again speaks to the quality of work that went into these coaches

Re: Pressure switches on front sixbag/bags

Reply #16 – January 30, 2022, 02:57:51 pm

Quote from: Elliott – January 30, 2022, 01:37:30 pm

That's in the silver HWH box right? (pic attached)

I don't see that combination and configuration of fuses. I do see eight 5amp fuses all evenly spaced behind one of the circuit boards but not the 10am or 7.5amp fuses

Yes that is the control computer for your slide and air ride control. Multable layers and fuses all over the place 680 unit. When I got mine back from HWH the ride height fuse was popped and actually had to trouble shoot it from the beginning. Been fine since. It was under once of the circuit board. Also had a LED identifying fuse was open.
Scott

Re: Pressure switches on front sixbag/bags

Reply #17 – January 30, 2022, 05:36:20 pm

So has anyone been able to source just the solenoid coil? Or do I need to pony up $100 for the entire RAP1940 assembly?

Re: Pressure switches on front sixbag/bags

Reply #18 – January 30, 2022, 06:11:09 pm

Give Northwest RV a call. See if they will sell just a coil. Doesn't hurt to ask.

Re: Pressure switches on front sixbag/bags

Reply #19 – January 30, 2022, 06:16:06 pm

More possible leads?

HWH Solenoid Coil

HWH system not going to travel mode

Re: Pressure switches on front sixbag/bags

Reply #20 – January 30, 2022, 06:34:42 pm

OR, like Mike says: get creative. Poke around on eBay and Amazon. See if you find something close. Check the center hole size on your old coil to verify it is 0.500"!

Question to EE majors: How do you measure or rate the "pulling power" of a 12V coil? How can you compare a generic coil to the genuine HWH coil to see if they are "close enough"? Just curious...

HY 6302012 - Hydra force Coil With Wire Leads 12 Volt DC Fits 08, 80, 88,...

HydraForce 6302012 Solenoid Valve Coil, Wire Leads, 12v DC, Series 08...

HydraForce 6302012 Solenoid Valve Coil, Wire Leads, 12v DC, 08 Series

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Re: Pressure switches on front sixbag/bags

Reply #21 – January 30, 2022, 07:15:10 pm

Chuck,

Thanks for the links.

Elliott,
Like I have said in another post long ago, I used a 12VDC coil off of some kind of snow blower to get a fellow down the road. Last time I checked that temp repair was still being used. Don't know when a temp repair turns permeant though. If you go with a bare coil you will have to cut the plug off the old coil and reuse it. Now if you want a new plug you need to open the coffers a little wider.

Mike

Re: Pressure switches on front sixbag/bags

Reply #22 – February 06, 2022, 07:59:04 pm

Quote from: Chuck & Jeannie – January 30, 2022, 11:30:54 am

You would need to follow each air line by hand from the manifold to see how it actually connects to the air bags. I have never tried to do that.

So I did this and there is indeed one line to each bag from the manifold. The diagram I posted in reply #7 accurately represents the airlines including where they connect to the manifold. So the two bags in each corner are connected via the manifold.

I fixed all the leaks between the front and rear tank, and replaced the bad solenoid and now I have lots of pressure at the bags

I can fit my stands in no problem with a couple extra inches to spare.

While I had the slide bladder tank dropped I pulled the six pack down and tightened the compression fittings. I've said this before but I feel it needs to be said again: there's a special place in hell for the engineer that put the front six pack there.

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