93 dakota outo overdrive problems

I have three speed automatic with over drive (little button on dash)
the light comes on when you turn it off but when its on it wont shift into overdrive it goes through the three gears just fine is there a sensor or something some one told me it could be that the engine temp is to low is that true? looking for some help thanks
:disappoin

Not sure if i understood the question correctly, but the button on the dash does not enabel the overdrive, it locks it out. When pushed, (light on) it should not go into overdrive. With light off, if it does not shift into OD, then yes, you may have a temp sensor, or an electrical connector, or solenoid preventing proper OD operation.