how can i by pass oil light with new one think i have open circuit in one of the wires to switch can this be done.?

Your oil pressure sender unit has malfunctioned and needs replacing. On old type cars it is normally located on the engine block and it only takes a couple of minutes to replace.

All you would need to for a sun pro gage is locate to oil pressure sending unit on your car and remove it attach the copper line were you removed the sending unit. that copper line come in a separate package don't use the plastic one unless you want a mess run the line though the fire wall and mount the gage the idiot light will still be on but you will know the pressure

You short the sender wire to earth,if the bulb goes out and then back on when you don't the circuit is fine and the oil pressure switch is permanently shorted to earth and the bulb will always be off.

if the sensor is not connected then the lamp "should" be always on.

new sensor.

Use meter to check the oil pressure sender and then replace if that is faulty