Have Toyota Questions? Ask a Mechanic for Answers ASAP
What year make and model do you have? Do the head lights work and the tail lights?
Do you have a simple 12 V test light or a voltmeter with a reasonable knowledge of how to use it? When you turn on the taillights or illumination does anything else work like the radio illumination or other switches and components? If they do and you turn the rheostat up or down does the intensity change? Are you 100% certain that the rheostat is not turned all the way down not allowing the illumination circuit to light up?