So just recently my D4 light comes on when I turn the car on but it doesn't affect anything on the car. Any ideas why it comes on and car works normally is it telling me something is wrong with transmission or just bad ignition switch but car doesn't turn off when I wiggle the key.

 

Does the D4 lamp stay on the whole time or just comes on when you start the car and turns off?
If it comes on and then turns off when starting the car that is normal check when turning the key to ON.
If the lamp stays on when the car is in any other gear other than D4 then there is a stored code.

Locate the two wire blue connector, Pass kick panel on 90-93, under glove box door on 94-97. Or use an OBDII scanner on '96-02 cars to find the code.

Report back with the code for further diagnostics.

Year, engine and submodel would help.