crapped out alternator mounting bushings could cause a loose belt, but they usually cause the belt to squeal when you rev the engine...usually.
my "L"ectric idiot light came on when i had a loose connection to the + lead...it was holding on by about 2 threads. re-crimped it and it fixed 'er right up.
good luck!
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'68 gray 2002 pig-cheeker - '74 verona 2002 - '74 turkis 2002ti(-i) project - '97 Ford Ranger parts hauler - '06 astro black MINI Cooper