If it's anything like my '83 SD, then you loosen the two screws and simply lift the fuse block out. It's hooked in the rear, set in place, and then screwed down in the front.

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John Schroader
bio burnin' 83 300D, '83 300 SD, '79 240D
"I've never met a man who was good at making excuses who was good at anything else" Ben Franklin
"You cannot permanently help a man by doing for him what he could and should do for himself" Abraham Lincoln