Some questions about LLS components (posted over on Expi forum, copied here for comment as well), any help/comment would be appreciated, thanks:

On the following solenoids, are they essentially all the same wrt specified performance; in other words, can they be swapped out/substitued amongst each other? They all look similar and are just electric solenoid operated check valves, but do they have different operating parameters?

Front fill solenoid - p/n 1L1Z5311AA
Rear fill solendoid - p/n F50Z5311CA
Front 'biasing' solenoid - p/n (?)


Also on these solenoids, can the air line retaining ring and collet (at inlet and outlet) be removed and a new o-ring replaced in these units? If so, is there a source for new o-rings available?

On the air compressor, p/n 1L1Z5319AA (or equivalent aftermarket), what is the average expected life given normal driving conditions and minimal or no leaks in a typical system?

On the compressor switch (inside the truck), p/n F3LY5K761A, has anyone ever had one of these go bad and had to replace them?

For intermittent CHK SUSP lights coming on, if you reset the system (by either turning off/restarting the engine or by cycling the compressor switch), does this do any harm to the system electronics or does the GEM module have fail-safe parameters that tell the system to shut down if it sees operating parameters (ride height, etc.) not reaching or staying within specs? Is there a hi temp cut off on the compressor?

Does anybody know of a source for an affordable GEM system code reader or some easier way of obtaining just the code from the GEM? (ie not the Ford recommended type, like the NGS STAR tester.)

On a related component; for the standard factory shocks on a 4x4 with LLS, how long do they usually last given light truck useage? Is it normally based on mileage or time for replacement?