Leveling switch question

[craiglenz]

After 5 months of getting the coach set up to handle my chair Im finally able to LEARN the prevost. Here is my first challenge. The leveling system up/down button is acting up. Acting up meaning if say I put the selector in the right rear position and then hit down I normally just hear a little pssst and thats it. Ive found if I rotate the selector to the opposite side which again i only get a short pssst of air below and if i keep rocking the up down switch enough times getting these little short air exhausts and move the selector enough times from left to right to front to left to right to front, eventually for some unknown reason the air will start to exhaust. From that point on it acts properly in any of the three positions. I can level the coach and it holds its level well.

My question is would it be the up/down switch or the selector giving problems. Since when it starts working all positions work its not in the norgrens. Doesnt seem to matter which of the selector positions its in when it finally starts working. At first i just had to move the selector a few times and rock the up/down switch multiple times to get it working. The last time it took about 10 minutes of playing around like this and then sure enough it exhausted once and worked fine to level all three points on the coach. Is the up/down rocker switch the first thing to test and if so how does one go about doing that?

Thanks for any experience you guys can share.

[Gary Carmichael]

Craig, I cannot answer your questions, but maybe Jon can? Have you made any trips yet? where do you keep the coach in the winter?

[Jon Wehrenberg]

Craig,

Several things come to mind but they are guesses because it is difficult to do analysis via the forum. There is no substitute for being able to have eyes, ears and the sense of touch at the coach.

When you set the switches and command the system to exhaust air (to lower a portion of the coach) solenoid valves in the steer compartment are taking those electrical signals from the switch you are moving and send air to valves that control the suspension system. So if there are any glitches in the system they could be in either of two Norgren spool valves, a solenoid valve, or the switch itself. The fact that with each command regardless of position you only get a short exhaust suggests to me the rocker switch that controls the up or down or the three Port Norgren in the steer compartment may be defective.

The reason for that suggestion is because as you change positions (left rear, right rear, etc) you are bringing into play different solenoid valves and different Norgren spool valves. The only components common to the different positions are those two mentioned above.

You should be able to set the selector switch to the left rear position (for example), depress the rocker switch that controls the up or down motion to the "down" position and hear air exhausting until the air bags have no pressure on them. You should be able to do the same thing with the same results in the other two selector positions.

The unknown in this situation is the age of the components (are they original) and if they have been exercised routinely and if the auxiliary air system has been maintained. There are potential issues that go beyond what would be expected such as water in the system that could produce symptoms that make no sense in a well maintained system.

[dreamchasers]

Craig,

I thought I would share a thought with you. I have a Country Coach that has a "rotary" switch that is used to select the position (front, rear, or sides) you are seeking to manipulate, plus a two position rocker switch for up and down. I have found at times, the switch will not function correctly. The symptoms are very similar to what you are describing. It seems that over time the contacts on the rotary switch become tarnished or dirty. If I spin the switch numerous times, allowing the contacts to close and open, it seems to "self clean" the contacts such that they function as intended.

I think that the rotary switch not being used for extended periods of time, causes the contacts to tarnish from non use. Working the switch contacts seems to improve the connectivity enough to function properly. I have not use contact cleaner on the rotary switch, but I am sure it would also help and keep the contacts cleaner for longer periods of time.

Give it a try. Hope it helps.

Hector

[craiglenz]

Gary, I just picked the coach up in Eugene Oregon this past week and am in Vallejo Califonia with it now so Ive only got 500 miles under my belt by am learning. Had hoped to have it up to Saskatchewan before fall but the renovations and lift install took longer (or should i say the vendor took much longer to get around to it) than expected. Too much salt on the roads and too cold now to take it north so going to take it south and park it till spring. Can only run on permits till i do my import to canada so am going to be limted on how much I can drive it but just dont want to take it into our winter road salt conditions. Short answer is in the winter i plan to be south like the birds :)

Jon thanks for the input. Strange things guys. I just went to try the leveling system now and its working fine. The bubble was right where i put it two nights ago so the system seems to be holding good. Only thing I can think that is different is it hasnt just come out of the drive position which is what has normally been the case. Ive driven some wheres and now i go to level it. Strange thing is is after I fool around and finally hear one good exhaust, EVERYTHING works good. It raises and lowers on all three points. Never hesitates when I shift from left to right or to front like it should if the selector contacts were not good. The up down switch works everytime like it should with no exceptions.

The challenge seems to be to get that first good exhaust after switching from the drive position to the other three to level the coach after having been in the drive position. Will let you know what happens next time I move the coach. Right now its working as it should.

Thanks guys for the input. Seems the trouble shooting will have to wait now till the next drive.

[Prevost.Rick]

graig call me mon your country has a secondary leveling system i,ll update you on c/c and prevost systems 813-833-2284 rick thank you

[craiglenz]

Well guys i moved the coach today after sitting for three days. Air held good and no leans. Before I left I tried exhausting the air and all worked well with the leveling system. All three points raised and lowered as they should. When I arrived at my next stop and went to level the coach same thing. Little pssts of air when i tried to lower any of the points. After chasing around the switches as before it started to work again. So it seems it is when the coach comes out of ROAD position that this problem occurs. Sorry Rick havent been able to get a chance to call but will make a point to tomorrow. If this spurs any ideas Im all ears.

On a side note I just had my inverters removed and serviced in Richmond California. They were new in 2005 and used very little. The inverters would go into overtemp when charging. Turns out BOTH had fan failures. Strikes me as strange they would both go out at the same time but they were both dead. Ernie the service tech there put them on his scopes and load tested them and all was fine. Put new fans in and were back in business. Have no idea how long they were out. Batteries were dead when i did my pre buy inspection and now with new batteries in the coach the overtemp issue came to light. Good to know now that the battery bay has been fully serviced. Couldnt be more happy with the service Ernie at Xantrex gave me. Highly recommend him to the group.

[tpr]

Craig,

I have had two Angola Coaches before my present coach. A 1991 MCI and a 1996 Prevost. The 96 had chronic air problems, prevost told me the air system was contaminated with moisture and gunk from the Jun Air aux compressor. They told me the aux aircompressor was tapped into the system after the air dryer(I don't know how true that was). The gunk would make the cylinders in the norgren valves either stick or move slowly to fill or exhaust air. After chasing leaks and stuck valves for a few years I had Prevost purge and clean out the air system and replace the norgrens. It helped alot, the only one that ever needed attention after that was the 5 way in the compartment under the drivers area. I always carried a few spare norgren valves just in case as any mechanic can change them. Angola made fine coaches and after you de -bug it you should have a comfortable and reliable ride.

[craiglenz]

This morning "The Bus Depot" in Las Vegas took a look at my leveling problem and ended up replacing one of the Valve Spools. Part # 641927. First they took apart the five valve norgren valve and inspected and cleaned it but all was good. Seemed to be a little unfamiliar with the 5 valve vs 4valve norgren which they run on the majority of the fleet coaches they service. One point I thought Id mention is now when the selector switch on the leveling system is moved from the drive position to the left, right or front positions it gives off a short exhaust of air. Didnt do that when it was giving me trouble. Since the coach is new to me I didnt pick up on it cause I didnt know that it should do that. Now its quite obvious. The learning continues but now the bus levels as it should. And for an added bonus it seems to hold it there.

Thanks guys for the input on this. If ever in Las Vegas John over at "The Bus Depot" on South Decatur Boulevard has a real nice four bay shop with full length pits on two, coach lift and a full service spot free wash as well. Highly recommend their service.

Merry Christmas Poggers,

Craig

[Jon Wehrenberg]

Craig,

One of the hardest parts of ownership is sometimes we do not have a benchmark for determining the difference between what is the correct operating condition, or an abnormal one. Anyone new to a Prevost might not recognize a problem with shifting, or Jake brake operation or suspension control operation. With respect to the suspension not all systems function the same because over the years Prevost made changes to the design and operating logic, and converters sometimes altered the system to provide some features. So in the case of the suspension even experienced owners changing converters may not be sure what is correct or a sign of a defect.

I don't have and have never had a pure Prevost level low system so for me to know if a short whiff of air is normal. Few of us can know every single variation and how each performs.

While I kid about us sometimes giving correct answers, it is the truth. We can only speculate sometimes.

Diagnosing any of the suspension systems often requires a hands on approach and a meticulous step by step verification each component is functioning as required, starting with the electrical side of the system and then following the pneumatics. It sounds daunting, but if someone undertands the system well enough it is actually very easy to follow through the system(s) and isolate the bad part or parts. And it can be done quickly. I did a diagnosis on a bus and in less time than it took to remove the bad valve I was able to zero in on the culprit, and taking it apart proved it was in fact what was wrong.

Diagnosing on a forum is also difficult because having eyes, ears and fingers on the bus is significantly better than trying to interpret the written word.

Glad you have it resolved. We have far too often felt the pain of a POG member who had his wallet vacuumed by service techs who were getting on the job training.

[craiglenz]

Thanks Jon and everyone who help us newbies learn our coaches. That's is absolutely true that with something new "to us", one doesn't have the ability to diagnose a problem based on "how it operated when it was working correctly" as was the case with this leveling system. One always questions if its the system that's not working right or if I simply don't know what "it should" work like. Fortunately for a coach that has such low miles for being 15 years old it seems that things are coming together and the butterflies are getting fewer and fewer with each new sound I awake to. :-)

Thanks again, Merry Christmas and a Happy New Year to all of you.