Do a search on this here, lots of info. You can probably fix the control box by re-soldering the 100+ connections on the printed circuit board. I did mine last year and it still works great. I used a low heat fine point iron and one of those illuminated magnifying glass lights (wife uses for jewellery work). You'll need to decide first if that's what you want to try, as the sellers of refurbished units won't accept a core that's been worked on.

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1986 560SL
2002 Toyota Camry
1993 Lexus