[Will]

The only 2 things that come immediately to mind is if you are not getting power to the level low switch that means none of the solenoid valves on your 4 valve manifold (5 valves on newer coaches) are receiving power to the coils and they are in-op. I would be concerned to the extent that I would want to be assured at the very least the 2nd valve down on the manifold is getting power when you are driving because that one controls the ride height and it is not safe to drive with that valve closed. If you have the means check to verify power is getting to the valve coil, key on. If not see if there is a way to at least jumper 24V power to the 2nd coil down. Look for tripped circuit breaker(s) or bad fuses. Likely in the front electric compartment.

The only other reason for nothing to work is if you are not getting any air pressure to the manifold. For the Norgren valves in the level low system to shift you need at least somewhere around 30 to 35 PSI.

[Archived]

Does the system have an auto-leveler, such as an HWH system? If so, and you loose the HWH system, it prevents power from going to the Prevost system.

[Archived]

Since we have a very effective level low system why do we need an HWH system? I have not used the HWH and frankly am not sure when I should. Always just leveled manually using LL.

[Robin]

My old coach does not have auto level. It is manual.

Thanks Jon for the response. I’m not very mechanically inclined. I opened fuse box but see no problems, so off to see Jeff tomorrow.

[Archived]

The standard level low system is on all Prevost shells. Because it is manual, some converters chose to make it more automatic by use of the HWH system or Liberty Coach designed and installed their own auto-leveler.

For both of these systems the Prevost system is still the backbone for their operation. They are “piggy-backed” onto the Prevost control manifold ( four or five solenoid control manifold) in the front service compartment. Then there is a control module mounted somewhere and a level device that is set for level and when out of level sends the appropriate command to the correct manifold down below. The coach is adjusted by just using the auto level mode.

As HWH did not want you to be able to use both systems at the same time, they interrupted the power wire going to the Prevost rotary switch, sent it to their control board and then returned it to the Prevost rotary switch. When using the HWH system, the Prevost system was not able to work.

Another thought: The Prevost rotary switch has numerous brass contacts on it. They can become corroded over time and not complete the circuit they need to. Rotate the switch round and round a few times to clean the brass contacts and you will get the function back. Kind of like old time television tuners!

[Archived]

Prevost,

Is there a workaround should the HWH fail allowing the use of Prevost level low? Failing HWH comes up periodically and would be nice to have a way to bypass the system.

[Richard]

I don’t think Hugh has HWH or any modifications to his level low.

But Tom’s question is a valid one and if nothing else owners of modified leveling systems should learn how to operate all the features of the level low, the supplemental leveling system and how to disable the supplemental system to retain full control of the coach level low system. Very important.

[victor]

For the early systems from HWH installed in the Prevost shells, the power from the circuit breaker was cut and the power went to the HWH control module and then back to the other side of the wire they cut to power the system. The HWH module was supposed to block power back to the Prevost level low rotary switch whenever the HWH was activated. The problem came from the HWH module if it failed. If it did, then no power back to the Prevost system. Later HWH systems had changes to prevent this as the normal was to let the power through the HWH module with no effect. Thus, if you lost the HWH module then the Prevost system stayed powered. But this was later in the 1990s.

For the earlier sytems when they failed you had to find CB82 and wire 24-85-16. You followed this wire as it went to the rotary switch. Along the wire you will find where it was cut as there is normaly a butt connector with a wire going off into the vehicle and then right next to it another wire returning to the place where the wire was cut. This was all in the front electrical junction box.

Once you find this connection you can turn on the ignition switch and see if you have power coming to the first splice connection on wire 24-85-16. Then check on the other splice connection and see if you have power there. If you do not, simply re-connect the two pieces of wire 24-85-16 and the Prevost system is now powered and the HWH is no longer in the level low system.

If for some reason you cannot find this splice of the wire, then gain access to the rotary switch and tind where wire 24-85-16 is connected. Run another wire from a fused or circuit breaker-ed connection to this spot and power the system this way. Or you can do as Jon has described before and simply supply the second solenoid on the manifold for the level low in the front service compartment with 24 volts and you are in ride or travel mode. This should at least get you down the road and home or to a repair shop.

The wire to the drive solenoid is 24-104-18. It was usually blue in color. Plus the later sytems had 5 solenoids and the drive solenoid was the third one down. If you can see the 1/8 inch black air lines that come from the rear of the manifold, the drive position is the only one that has a T-fitting in it as it sends a pilot or control air signal to the front and the rear Norgren valves for the drive position.

[Archived]

Thanks Prevost, we’ll put this in the repair nugget topic so it’s readily available.

[Archived]

Thanks for all of the replies to this thread. I picked my coach up at ETLS this AM and Level Low is repaired. Problem was broken wire.

Thanks to Jeff and the team.

Now on to greater and more difficult problems!!