[bestgenman]

I’m guessing your problem is the slug, or movable part, is sticking.  This happens on my set once in a while.  The solenoid is really two coils of wire making magnetic force.  One holds the slug in, which you proved working when you manually pushed it in and it stayed.   The other is pull in and you’ve also proved it is working.  The fix is gently peel the boot away and remove the slug.   Clean it and apply a dry lubricant such as graphite or molybdenum disulfide,  nothing that will dry like WD40 will work.   Or, buy a new one.   Martin will have them and the air springs as well.