Is the MPX B identified as MPX Multiplex Communication System? Mine keeps blowing out after my battery was drained and the altenator 20amp fuseable link blew. 20 amp link replaced, does not blow alt charges correctly. MPX B and interior radio fuse blown, both replaced, MPX B blows with engine off key out of ignition. Dont know where to go, only have Haynes 92076 Toyota book. additional info, pulled stock radio put in 15 year old raido, will drain battery if not turned off or pulled (removes from chassis, old school). think it might be harness pinch, but dont know where to start checking...

 

Opps!! my bad, not the MPX b fuse but the Dome fuse right benieth it......went through and found that it is the Antenna Relay (power antenna) that is "F"d up. unplugged it. no longer blows fuse......

Ha ha ha ha.