Okay. So you appear to have proven out the control switch by getting 12 volts on the red/blue and red/yellow but I just want to make sure that is accurate. If you are getting the 12 volts as shown below then I am wondering if this is as simple as a dimmer switch issue. The Red/yellow wire is basically the ground. It just has the dimmer in line. The way that works is as you move the roller it increases the resistance which will dim the lights.
Anytime you increase resistance after a load in a circuit like a bulb it causes the load (bulb) to use less voltage because it requires some voltage to get past the resistance and get to ground.
So if you have a bulb with no resistance after it then you will have full illumination from the bulb because you require very little voltage to get to the ground stud. However, if you increase that dimmer switch then that will require more voltage which means the bulb will get a smaller share of it and it will dim.
So if you have 12 volts on this wire then that dimmer switch is all the way up and is taking all the voltage from the bulbs and they are not illuminated.
If you notice as well, the glove box is the only one not on this dimmer switch. Even though you cleaned it, I suspect it is the issue.
Image (Click to make bigger)
Saturday, January 18th, 2020 AT 7:44 PM