Before you tear into things trying to diagnose the problem, I suggest that you take apart all three switches. Then clean and lube the contacts.

After that I would be looking at the leveling air switch / valve on the failing side. You can disconnect the operating rod on it and force it to move up and down to see if works. There is a time delay on those leveling valves. If you need one, Jim K. has new ones. Also Dave Lenzi rebuilds them.

Electrical conductor between the "lower" side of the switch and the air
solenoids near the rear location of the compressor/tank unit. I would
suspect the multi pin connections worst of all.
Jim Hupy

Ken Burton wrote on Sat, 25 October 2014 17:26

Before you tear into things trying to diagnose the problem, I suggest that you take apart all three switches. Then clean and lube the contacts.

After that I would be looking at the leveling air switch / valve on the failing side. You can disconnect the operating rod on it and force it to move up and down to see if works. There is a time delay on those leveling valves. If you need one, Jim K. has new ones. Also Dave Lenzi rebuilds them.

Thanks for the response Ken. All three switches have been cleaned and lubed with "Corrosion X". I did take the operating rods off and moved them manually. After the built in delay, both would work for raising the coach, but would not lower the coach. Both leveling valves are rebuilts from Dave L. Guess I should have mentioned this in my original post. Any other ideas??
Thanks.

Larry wrote on Sun, 26 October 2014 07:50

Ken Burton wrote on Sat, 25 October 2014 17:26

Before you tear into things trying to diagnose the problem, I suggest that you take apart all three switches. Then clean and lube the contacts.

After that I would be looking at the leveling air switch / valve on the failing side. You can disconnect the operating rod on it and force it to move up and down to see if works. There is a time delay on those leveling valves. If you need one, Jim K. has new ones. Also Dave Lenzi rebuilds them.

Thanks for the response Ken. All three switches have been cleaned and lubed with "Corrosion X". I did take the operating rods off and moved them manually. After the built in delay, both would work for raising the coach, but would not lower the coach. Both leveling valves are rebuilts from Dave L. Guess I should have mentioned this in my original post. Any other ideas??
Thanks.

OK, I'll go dig out the diagram and figure out how it works.

Larry,

Here is what I remember and think. Let me qualify that I'm not an expert in this area and could be wrong. The lowering function in controlled by the leveling switch and it exhausts the air right at the sensor. In the sensor there is one small port that goes no where except to the outside air. Buried inside that port is a special schrader valve with a very weak spring that allows the air to exhaust but not enter. So when the sensor is in exhaust, air will be depleted from the bag if the hold solenoid is powered. The hold solenoid / valve is powered with the key on and switch is in travel.

The air path between the sensor and bag is: sensor to n/o raise solenoid, to n/o lower solenoid, to n/c hold solenoid, to the air bag.

So my first guess is those schraders in the leveling sensor. I would disconnect the rod on the leveling sensor. They turn the key on and move the rod to cause the bag to loose air. If nothing happens after the time delay, then remove the schrader and move the sensor lever again. If there is still no air loss then I would slide a block or jack stand under the coach and disconnect the hose from the leveler that goes to raise solenoid. I'm sorry but I do not have the hose colors on this diagram. There are two hoses. One goes to the air tank manifold and the other to the raise solenoid. If you pull the wrong one, the air tank will go empty but the bags should stay up if the sensor is in the neutral position.

If after disconnecting the correct hose and moving the sensor rod if the air stays in the bag then the senor is not your problem. You are going to have to trace the problem back through the raise, lower, and hold solenoids.

I sent you a diagram that I have on my laptop illustrating this.

I'm thinking strongly at this point that your problem is in the exhaust schraders.

Ken

Ken Burton wrote on Mon, 27 October 2014 09:46

Larry,

Here is what I remember and think. Let me qualify that I'm not an expert in this area and could be wrong. The lowering function in controlled by the leveling switch and it exhausts the air right at the sensor. In the sensor there is one small port that goes no where except to the outside air. Buried inside that port is a special schrader valve with a very weak spring that allows the air to exhaust but not enter. So when the sensor is in exhaust, air will be depleted from the bag if the hold solenoid is powered. The hold solenoid / valve is powered with the key on and switch is in travel.

The air path between the sensor and bag is: sensor to n/o raise solenoid, to n/o lower solenoid, to n/c hold solenoid, to the air bag.

So my first guess is those schraders in the leveling sensor. I would disconnect the rod on the leveling sensor. They turn the key on and move the rod to cause the bag to loose air. If nothing happens after the time delay, then remove the schrader and move the sensor lever again. If there is still no air loss then I would slide a block or jack stand under the coach and disconnect the hose from the leveler that goes to raise solenoid. I'm sorry but I do not have the hose colors on this diagram. There are two hoses. One goes to the air tank manifold and the other to the raise solenoid. If you pull the wrong one, the air tank will go empty but the bags should stay up if the sensor is in the neutral position.

If after disconnecting the correct hose and moving the sensor rod if the air stays in the bag then the senor is not your problem. You are going to have to trace the problem back through the raise, lower, and hold solenoids.

I sent you a diagram that I have on my laptop illustrating this.

I'm thinking strongly at this point that your problem is in the exhaust schraders.

Ken

Thanks so much Ken!! I'm gonna look at it this afternoon, while the weather is still good. Tomorrow...cold and rain.

Don't forget to drain the water separator when winterizing. Guess how I know this!

Hal Kading 78 Buskirk Las Cruces NM