They don't protect the MAS because they are the MAS. OVPs didn't disappear they just aquired different names and definitely got more complicated. The succesors are variously called MAS, BASE, and most recently are the group of relays called K40/x.

I guess GM never used them because it was easy to throw a controller at a GM car as they are only a little more than double the cost of a OVP (late model) and they failed more often than OVPs anyway.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician