Welcome to the GJ!! The trigger controls the positioning of the handle. Chances are if you are missing the trigger you might also be missing the positioning control rod since this it what the trigger attaches to. Parts for these old Blackhawk units are pretty much obsolete and very tough to come by unless you have a donor jack. However, I might just have an extra trigger assembly, I'll need to check some part numbers to verify that it is correct.
Also, I won't be able to release any parts to you until you post some nice detailed pics of your floor jack.....it's a GJ mandatory policy, and I have to obey the rules.
