Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 12, 2025 ...

Juicesqueezers, do you have the air schematic?

The dash gauges show the front and rear brake tanks. Not the wet tank nor the slide seal tank. You need a gauge near the aux compressor to see whats happening at the s/o tank.

Here is another thought about this rapid compressor cycling.

After looking at a generic air schematic for a 2000 (not the one for his exact coach) it shows a ball check valve just past the pressure switch. If this check valve has failed and is stuck closed it could be slowly bleeding through causing the pressure switch to see a need to come on. When the piping between the 2 is up to pressure the pressure switch is satisfied and shuts the compressor down.

Mike

I feel a sense of frustration when I read threads like this.  You have a simple problem: your air compressor runs at the wrong times or shuts off at the wrong time.  It is cycling on/off rapidly.  Why?  It should be fairly easy to solve this problem with simple trouble shooting skills.

Step 1:  What powers your air compressor?  You know the answer to this because you have removed the fuse from the power wire.

Step 2:  What tells the compressor to turn ON and OFF?  You already know the answer to this because you have taken the cover off the pressure switch and pointed it out in your photos in Reply #10.

Step 3:  If compressor is getting power (YES) but is turning ON or OFF at wrong times/pressures, what causes this?  Answer: the pressure switch.

Step 4:  How best to solve the problem?  Answer: replace the pressure switch.

Discussion.  The pressure switch is similar to the ones you will find on many air compressors, and also on water well pump controls.  It employs a diaphragm to sense pressure, and spring loaded contact points that open and close to control power to a motor.  One common problem is that the contact points will get dirty or eroded, and will not maintain the proper gap.  Bad/dirty/corroded points can cause the switch to act erratically.  If this IS the problem, you can "dress" the points (clean them up) with a "points file" and possibly restore proper operation...temporarily.

Another possible problem is the diaphragm can develop a tiny leak, causing erratic switch operation.

Another possible problem is the port into which the switch is installed can get plugged up with junk, causing erratic switch operation.

Occasionally, the switch operation can be restored by screwing the adjustment nut (on top of the big spring) in or out a bit.  This nut is normally used to raise or lower the "kick in" and "kick out" settings on the switch.  You could try messing with it to see if it makes any worthwhile change in your compressor's operation, but it probably won't help.

Once again: the SIMPLE solution is replace the pressure switch.

Once your compressor is back to operating at correct times and pressures, THEN you can go hunting for air leaks.

If anyone has the part number for this switch, I would appreciate you post it.
I know that Roger suggested the pressure switch as well in a previous comment.

if you look at the photos I posted at the begining, see if that brass rectangular block is the valve?  That just might be it. 

Joe,

I have been looking at both your pics. and the generic prints for your year coach that I have. The first thing I see is some of the stuff in the pics. must be for an air operated awning.  According to what I can see in the prints that I have you must have a check valve either in that square block or in one of the fittings that are screwed into that block. This is the piece that has the drain valve, air lines, and pressure switch connected to it.

One other thing that you have mentioned in an earlier post is that before this problem of rapid cycling that little compressor would air up your main tanks. You stated that this was visible on the dash gages. This leads to your 2nd problem in that you have a isolation valve that is leaking from your seal air tank back into the front dry air tank. Do you have an air tank switch on your console?  If so the valve that is connected to that switch is what is leaking through charging your main dry air tanks. That little compressor isn't designed for such service and can cause it to fail prematurely.

Mike

I am going to give Derek a call next week and see what he says and order a print out of our air system from FOT.

so I pulled the 20 amp fuse that is located at the compressor and that stopped the compressor from coming on. 

Ok maybe I have this backwards... I always thought the front and rear air gauge was for ride height? It is not? its for the brakes?

My front gauge stopped working after the rear axle seal replacement... next on the list to find the issue.. was thinking 6 pack but now I am not sure.. no work was done anywhere near the six pack..

Mine calls for a 5amp fuse.  20 amp seems kinda' stout.

Ok maybe I have this backwards... I always thought the front and rear air gauge was for ride height? It is not? its for the brakes?

David,

The front and rear gauges are for the front and rear dry air tanks, they don't just read for the HWH ride height.  They are storage tanks that serve the brakes and all aux. air operated stuff like retarder, horn, HWH, and step cover.

Your 02 should have the magic box like Cman mentioned that converts air pressure to an electronic signal and sends that signal to the electronic gauge.

Mike