Did you ever fix your unit?

 

something like this could definitely be simplified.

 

Great video and detail of how it all works pneumatically, amazing ingenuity!!!

Yes it could be simplified, the hardest part would be finding small 12V Air Valves, usually these are 24V /110V operating. Miniature SMC valves might operate down to 12V but that would need verifying.

Aluminium SMC manifold blocks are readily available, perhap one of these could be modified to fit, although the Air Sensor tapped hole may prove difficult to machine.

It might be possible to 3D print an entirely new valve manifold which could then be exactly the same style and shape. 3D stainless can be print but its very expensive in small quantities, plastic is cheaper but not as strong, however it is a possibility after all the original is plastic.

I have a valve unit here that I stripped-down and serviced, if I get time I'll take a look and see if it could be printed.

No doubt Hmmr would like the air-sensor

 

you can probably use 12volt horn solenoids for air horns. and the sensor can probably be fitted to a reducer adapter to fit a air block manifold.

 

Yep - there are plenty of 12v air solenoids available as well as manifolds, etc. Not just for the air horn kits but for air brakes and air suspension systems used on trucks and other equipment. I've sourced air line, and even an automatic mechanical leveling sensors at a local Kenworth dealership service department for ambulances I've worked on. Most of the commercial stuff uses the auto-mechanical style valves which install in a similar arrangement to our height sensors in that the auto-mechanical style valves have an arm that relies on the suspension angle to determine whether to dump air out of the air springs or to allow air into them.

Haldex, Velvac, Wabco, and probably a few others are big names in the commercial end of things.

On mine I do plan on eventually adding an air tank, swapping the compressor for a much beefier and higher CFM one, and air horns.

Coincidentally, mine has just recently started acting up on me. Twice now in the past month, I've noticed the compressor running. On shutting the H2 off it kept running but the suspension was not going up or down ar anything. Just unplugged the control plug underneath at the back to get it to shut off. Next morning suspension has not sagged down or anything, plugged it back in and has been fine. So I suspect either a sticking relay or possibly a leak before the solenoid to air springs. Have not had time to mess with it though and seems to be working fine again for now.

 

MixManSCThis is curious, as far as I know the compressor can only operate whilst the engine is running and the sensor will only be reading the ambient manifold pressure. The Compressor Relay (under the hood) is directly controlled by the AS-Module electronics which is "Hot "all the time, so any error in the module itself could cause the compressor to run, so let's hope its not that

Next time, if you can, plug-in your TECH2 and check the Compressor Relay Status and Air-Pressure, you should be able see these even with the ignition off and the key out (at least I could)

If the TECH2 shows "OFF" and the compressor is still running, then if the realy is not energised it could be stuck as you say. If it is energised then the module must be driving it, but its hard to see what it could be other than faulty drive electronics, a short or something else unknown happening.

If the CPU output reads "Off" but the output transistors are "ON" the either the CPU line has "latched" or the there's a fault in the output circuit which is literally only a few components.

This would be a bit like the Blower Controller staying on.

Again you can't turn the compressor On/Off without the engine running, you can only see its status.

The ambient manifold pressure reads 41psi (15psi ?) with the shrader-valve on the tire inflator pushed-in, as this valve sits on the compressor line I don't think a leak would matter.

 

the even odder part is there was no visible indication of the truck highering or lowering so what was the compressor outputting to. just directly dumping it? or leaking between the solenoids and compressor or leaking compressor head?

 

Since it was not actually raising the suspension I can only assume that it was in some manner going to the dump valve like I'd assume it does when you manually activate the compressor using the switch in the rear for the accessory inflator. I have not checked that switch but I do know nothing was in the back that could have hit it. Plus that switch switch does not work with the vehicle off anyways. No apparent leaks. The air springs are only about 3 years old. Hitting the button on the dash still raises and lowers the rear as expected.

Was off to shut it off and the compressor keep running. The first time I only even realized it was running after I shut the engine off. The second time a couple of weeks ago I noticed it on at a stop light, turned the radio down and could hear it running. Stopped about 2 miles later and unplugged it. I need to start carrying the Tech2 with me in it in case it does it again but I'm reluctant to leave that in there all the time and its quite cumbersome to carry in and out with me all the time... So hopefully if it does it again I'll be in a position to get to my shop asap so I can connect the Tech2 up and try to see what it is doing.

 

hopefully it's as simple as a sticking relay as ocenbrave mentions

 

One thing, I've stupidly been referencing a twin compressor system, yours is most likely single, the units look quite different so it could be something else.

From the drawings the Compressor Relay looks difficult to access.