ECU B1 and Radio Fuse blowing.

[Alberto9324]

Hello, I currently own a lexus lx470 2002 with the Mark levinson and the navigation screen. One day suddenly i got the Audio Off message, and realized all my trips go to 0.0 and my time resets to 12:00 i think. My fob with the remote doesnt work to lock or unlock. the lock/ unlock in the interior doesnt work either.
my mirrors dont move up or down but they do fold. The screen works but will turn off after climate adjustment but cd, casette, radio: none work.
No sound from speakers but i do get the start up chime.

I have currently watched and read many forums here and I have tried.
unplugging the radio. fuse blown
unplugging the cigarette lighter connections, both their fuses and their lights next to them. fuse blown
removing the mirror fuse, leaving it in the middle position. fuse blown
disconnecting the battery, letting sit, putting in fuse. plugging in battery. fuse blown
the moment a 20amp fuse touches the Radio or ECU b1 fuse slot, immediate spark and blow.

the only thing I haven't done yet that forums say is unplugging the amp from under the seat but i doubt that will fix.

what are other things I can check, I'm running out of things to check but if needed can try to follow diagrams shared in another post about this that show radio fuse and other cables and their connections to other modules.

(Discovered the Main 100amp fuse leads to nowhere and forums say our cars in USA dont have them. )

 

[Alberto9324]

JANUARY 19 2026 UPDATE

I THINK I FOUND THE PROBLEM AND SOLUTION

i decided to go under the passenger seat and unplug the navigation computer and also the mark levinson amplifier.
i found the brown ground wire that is next to the amp had 12volts going to it and was sparking.
after moving it around a bit it finally showed zero volts.
and i was plugging in 1 thing at a time and checking the fuses.

suddenly the green ring around the key works.
the car dings cause key in ignition.
my radio antenna works
and the navigation screen came back!
and the fuses no longer pop!

all is good now. my only problem now is there is no speaker sound.
it very well could be the speakers themselves now, but i'll later check the speakers another time.
now the ECU B1 and radio 20 amp fuses aren't popped!