-
Coil- Road Height
Good morning all,
Need some advice. I have to fix this pesky Road Heght issue for the 500 mile trip to Jeff’s place in TN.
The ride height on my coach has been an issue. Driving down the road, the front drops after a while, the ride gets harsher, I have to pump it up manually. There are some leaks that Jeff will help resolve and overnight the front drops to the bottom. After I start the engine, the coach would not go to Ride height when the switch would be in the middle (Road) position. Manually I can bring it up in all positions.
So…. the sterm valve was replaced for the solenoid in the 3rd postion. I took a coil from the position above and put it in the 3rd slot….the coach came up. My conclusion, the relay is bad. Ordered a couple relays from Liberty because the one I took off and the the ones that are in the other positions say 12V on them and I thought this is the fix.
Well, it worked a couple times while stationary and then nothing. Back to square one….I turn the key to the On postion and reach through the window to flip the switch to hear and see what is going on in this coil stack….so what do I find….
When the switch is in either Manual or Auto position, there is a Potter & Brumfield 12V relay ( clear plastic housing) right above the 5 coil pack under the driver, that gets energized cutting the power to the wires that that control the Road Height solenoid in 3rd position- Blue and black wires. In the middle postion of the switch (Road), the relay is Normally Open allowing juice to go down to the solenoid…..now the problem…I put the voltmeter on the leads coming to the relay and I get 24 V !!!??? This is supposed to be a 12V coach. In Road position, the the 12V Potter relay opens the contacts and allows the 24V to feed the coil. I put a new coil into the Road position stack, the coach came up but the relay gets very HOT after a while. I think they burn up from voltage.
Question for the experts….Is it possible or even normal to have the Road height controlled by a 24V relay and the rest of the Air Low system in 12V configuration ……or maybe the relays were changed in the past with the wrong voltage ones ?
-
4 Replies
-
Mine is a factory non modified prevost. All coils are 24volt. Your converter might have modified system. But if you did not read 12 volt it apears that it is more like mine 24 volts control . I have a 98 XLE the e stands for entertainer. The app on mine is stock factory installed prevost. FWIW
-
Marius,
Do not overcomplicate a simple issue.
The bottom line is if your slector switch is in the road position you should have power to the center coil on the five solenoid manifold. Make sure you have a coil of the appropriate voltage and the center solenoid valve should be open. If it is supplying air your ride height valves should be active.
I test as follow. With the switch in the key on and road position I should have power to the center coil. If I do I crack the air line from that solenoid to verify it is open by virtue of air escaping. If you have issues with it coming to ride height I believe your vintage has five port Norgren valves that shift accessory air to the ride height valves and thus to or from the air bags.
Whatever is in between is window dressing unless it doesn’t work.
-
Yes, you could have both 12 & 24. My 94 Liberty had both, don’t remember if the 01 had both.
-
Thank you all for chiming in.
I just got off the phone with Liberty in Stuart FL.
All 12V coaches will have 4 (four) 12V coils at positions 1,2,4 and 5 and a 1 (one) 24V coil at position 3. They decided to keep the Prevost coil and 24V voltage for Road height.
So, it looks like everybdy has a 24V in 3rd position…..no coaches were done with 12V coil for Road height control.
That is why I burned the brand new 12V coil I just changed, why the old one was toast, why the coach would lose height going down the road etc.
BTW the Potter-Brumfield just above that allows the 24V to go to the 3rd coil HAS TO BE 24V as well – Model KRP-11DG-24
It is 12V on mine, gets hot and has to be changed asap…Ordered both correct ones.
Log in to reply.