Where is the location of fuel cut off switch on a 1990 dodge dynasty?

There isn't a readily accessible, easily identifiable "fuel cut-off switch" on a 1990 Dodge Dynasty like you might find on some other vehicles (e.g., some boats or RVs). Modern cars generally don't have these as a standard feature. To stop fuel flow in an emergency, you'd need to disconnect the fuel pump's electrical connection or deal with the fuel lines themselves – neither of which are recommended unless you're familiar with automotive systems and have proper safety precautions in place.

If you're trying to stop fuel flow for a repair or safety reason:

* Consult a repair manual: A factory service manual for your specific 1990 Dodge Dynasty will give the most accurate location of the fuel pump relay and the fuel pump itself, allowing you to disconnect the power. Note this involves working with potentially explosive fuel.

* Professional mechanic: It's safer and far more practical to have a qualified mechanic handle any fuel system work.

Attempting to disable the fuel system without proper knowledge and safety precautions is dangerous and could lead to injury or damage.