Instrument screen and panel light dimming

I've got a Garmin stack, GNA 340, GNS 430, GNC300XL & GTX327. These all came with a nice wiring loom already made up and thw wiring loom has lots of little yellow wires coming from it. I have followed the wiring diagram for the loom and the physical pin numbers which suggest these wires are for dimming the xcreen displays. But I can't find anywhere what to hook these wires up to. I assume a variable resistor/potentiometer. How do I work out what value I need?

Can I hook these up to the same pot I hook up the panel flood lighting (I'm probably going to use some of the little Vans black ball lights or maybe some of the electroluminescent tape)

I've also got a Dynon D10A and EMS 10 and trutrak ADI which have inbuilt lights that I need to dim and I need to know whether I need to separate each of these systems or can work them from the one dimming control.

What is the wisdom on this?

Put in a panel dimmer. Perihelion Design makes a nice one. You might not want the instruments connected to the same as your fllood lights.

I put in 4 dimmers as follows:

Control of a glare shield mounted EL strip light.
Panel lighting for those items using pilot controlled lighting.
Pilot Goose Neck light.
Copilot Goose Neck light.

The GTX-327 gives you an option of using an external dimmer or using front-panel controlled lighting.

Jeyll

The 430 and 327 at a minimum have auto-dimming. If you leave the dimmer leads unconnected, a sensor on the unit will adjust the brightness. You'll have to check the other units.

Dimming

I used an LC-40 from Vans and it looks like it's doing a good job with 4 dimmer channels. I use one channel each for Panel radios/instruments, Overhead panel flood (EL), CP Map, and PLT Map.

I'm not sure about the 340 but the PS Engineering audio boxes didn't have the internal dimmer so that had the dim lead. Everything else in my radio stack (480/SL-30/327) has internal dimmers which seem to work well.

The only other item on the panel that need the external dimming is the Compass.

Jim