guy on the squad bought a used code 3 vcon 37926 L6 for our "new" 1990 suburban it has 4 push buttons on it. 2 will stay latched when pressed. 2 wont...
There is an instruction in the manual how to change them from on-off to momentary it involves using a needle nose pliers to move a steel wire spring inside the switch from one side to the other, while pushing in the button, as I recall, it is the same procedure for a mastercom.