Diode And Resistor To Make LED Glow Dim

Hello, all. I am trying to find the value of a resistor, and the number of the diode I need to Make an LED glow dim, from the dash lights, then go bright when switch is on, but not feed back full +12 to the lighting system. Hopefully the pictures will explain. The first 2 pictures are of the switch, from Amazon. The last pictures show the connections when switch is OFF and ON. In the diagrams, the Switch is GREEN The LED is YELLOW The Trigger wire to the Relay is BLUE Ground is BLACK. RED 1 goes to the dash lights through a diode and resistor in series so they 1) lower the brightness of the LED, 2) block the full +12 VDC RED 2 from flowing badk theough RED 1 to the lights. The resistor and diode connected to RED 1 are not shown. I need to know the value of the resister to diminish the LEDs brightness to about 1/2 when the switch is off, and the number and orientation of the diode to keep the full voltage of RED 2 from flowing back to the lighting system. When the switch is turned ON, RED 2 to RED 1 are connected, as are GROUND and TRIGGER. Any help is appreciated. It's been years since i've done anything like this. I want to be able to see the indicators of the switches at night, but not at full brightness until they're turned on. Then you everyone. James