Hey all; I thought it might be fun to practice our troubleshooting skills. I'm going to list the symptoms of a problem with my 39ft 1993 coach. I will progressively add to the symptoms as the discussion carries on. Currently the problem is solved but I thought we could have some fun and exercise our knowledge of the system.
Following removal from storage the following symptoms appeared:
- From "dumped" position the left rear would raise slowly and very little rise when the "raise rear" button was pushed. The right rear would rise just fine.
- From the "dumped" position when the "travel" mode was initiated both sides of the rear rose together.
- When the "dump" button was pushed, both sides of the rear dropped at about the same speed.
- The resistance across the left rear raise solenoid coil was the same as the right rear raise coil.
- When the "raise rear" button was pushed the voltage on the input of the left rear raise coil was the same as the right rear raise coil.
- Both rear raise coils showed zero ohms to ground - that is the ground wire appeared to be grounded.
- When the raise solenoid was actuated it was heard to click and magnetism was detected on the center post.
So, what do you think might be causing my left rear airbags to fail to raise that side of the coach and what would you do next? have fun.
1st, it tells me that since the issue does NOT appear to occur in the travel mode, so it is likely NOT the ride height valve or the travel mode solenoid.
I would focus on either a stuck dump solenoid for the left rear (could be the left rear solenoid has debris in it preventing it from closing you should hear air releasing all the time the coach is in level mode if the dump solenoid is stuck open) OR a blockage in the six pack to the left rear raise solenoid or in the line from the six pack to the left rear airbag.
I presume you have tried putting the coach in travel mode and letting the bags all air up and then switching it back to level mode and exercising the dump valve for the left rear.
I'm with mike, stuck raise rear plunger in the solenoid or something stuck in the orifice do the raise solenoid valve.
Michael: yes I have air up the suspension in the travel mode (it worked normally), then dumped the air (that too seemed normal), then attempted to raise the rear with the same results noted above - the right rises and the left comes up slowly about an inch and then stops rising. There is no sound of leakage from the left rear dump valve. In addition, the suspension holds position for days so I assumed there was no leakage contributing to my problem.
The following additional steps were taken. I disassembled the left rear inflate valve and found no evidence of debris nor could I detect a struck plunger. In the process I left a bit of air pressure in the bags prior to removing the valve on the belief that the release of air might blow out any debris. I also opened the air shutoff valve I have installed on the inlet to the 6-pack and got lots of air pressure blasting my face. This wasn't surprising since the supply to the HCVs comes from the 6-pack connection on its bottom side. I then called HWH requesting to talk to a tech. The only thing he could think of was that there was some problem with the solenoid valve so I ordered a couple replacements. When they arrived I replaced the one that seemed to be at the center of the problem with a new valve. None of the symptoms changed at all.
So guys what would you do next? Remember we are doing this exercise for fun so don't make yourself crazy.
Wow. This is a brain tease. Can I check for understanding?
Air supply to six pack is proven good.
Left rear raise valve is good.
Voltage and ground to LR is good.
Air bag piping from six pack to bag and air bag integrity is good since it raises on travel, and holds once raised.
If I have that right, there is good air into six pack. And system integrity downstream of six pack is proven. Air solenoid on LR is working properly.
Is there a blockage in the aluminum six pack manifold?
Yes Richard you have understood correctly. In regards to your question about the 6-pack blockage, that didn't make sense since the travel valve is the furthest one from the outlet tubing to the airbags, with the dump valve the closest to the outlet. If those seem to be working OK then what can be plugged in the 6-pack block that would produce what we have seen.
Richard is absolutely correct that this is a real headscratcher, I've got a lot less hair as a result of this problem. Given all this, hey guys, put your thinking caps on and suggest how you might figure out where the cause of the problem is located. Location is key.
I would take my handy dandy solenoid valve isolator setup and install between the six pack and the outlet line to the left rear. For those who aren't familiar, it is simply a ball valve with guages on both sides. You install as I described, and depending on what the gauges do, you can figure out where you do and do not have air pressure.
You don't have a tag IIRC, so that rules out some issue with the tag dump raise valve not operating correctly.
Richard: very clever. The reason I took the different path described below is that I was having a problem related to the flow through the system, not so much the system's ability to hold pressure. Well, that and I didn't have two pressure gauges handy - actually I don't know how I would have proceeded if I had had the gauges handy.
Here is what I did, and really should have done at the start and saved myself time and money. I dumped the left rear airbags, disconnected the tubing connecting the 6-pack to the ping tank, connected the tubing through a valve directly to my portable air compressor and opened the valve. It behaved just like when I operated the raise solenoid valve, that side of the coach would slowly rise about an inch and then stop. The only thing I could figure was that something really weird was happening in the tubing from the 6-pack to the ping tank. I went to Fleetpride and got new tubing and installed it. I did not notice any problems with the connection at the ping tank nor with the tubing I replaced, but it all now works as it is supposed to. I have no clue what was going on with the original tubing that would cause it to restrict only high pressure air and not the air to and from the HCV or the dump valve. I just could not believe the simplest part in the system was the culprit.
Hmmmmmm, I can't figure out how the side would dump if the airline were constricted. Not saying you didn't fix it, but maybe there is a clue there.
Perhaps a bit of debris inside the ping tank connection that dislodged & fell back to the bottom of the tank when pressure was bled off to replace tubing? I once spent 2-3 days tracking down an intermittent fuel supply problem. Engine would starve out & die. Then run just fine for a while & repeat starving. We changed filters several times to no avail. Finally found a dead honey bee that was getting sucked up in fuel intake causing the starvation problem. As soon as the engine died, gravity would drop the bee back to bottom of tank until convection currents in the tank brought it back to the suction intake. The fuel intake did not have a screen on it.