1992 SC300 No Power to outside mirrors and radio

[Joseph Welsh]

Will a diagnostic test indicate if the Mirror ECU is bad?  The manual indicates that power to the ECU comes from the Dome 10 amp fuse and the radio 20 amp fuse which both have been tested and are in good working order. To get to the mirror ECU requires a lot of panel removal which is abs plastic and maybe broken in the process. Does anyone have experience in getting to the ECU for replacement?