The light board puts out 6VDC, so if you put a 220 ohm resistor in series with the headlight LED's, that will do the trick.
Auto cab lights will require additional logic, I'm assuming you want them off when moving and on when stopped?
The number boards are the same as the headlight, 6V from that lighting board. You can do those the same way with a 220 ohm resistor for each number board LED.
The class lights should already be LED, they are powered from the red connector.
