Your 1987 Chevy Celebrity starts and then dies and wont start and somebody said it was the alternator switch where do you find the alternator switch?

In all of my years working on automobiles I have never heard of an "alternator switch". Not too sure what that would be or how it would affect the engine running unless perhaps you battery is too discharged to run the engine.

Two things are required for an engine to be able to start and run. Those are gasoline and spark. So the first thing to do is find out if you still have spark and gas when the engine is not starting. To do that check the fuel pressure at the schrader valve, it should be about 45 lbs not running, it will drop some when the engine is running. If there is not enough ongoing pressure the gasoline will not be able to pass through the fuel injectors.

If you have fuel pressure then check the spark plugs for spark at the plugs. I do that with and inductive timing light.