I tried hooking it up as you suggested Mark, and got the same results as you; my drycell voltage was around 12 VDC instead of 9 VDC like your setup, and still the amber light is pretty dim, to the point of being unusable in normal daytime situations driving.  To keep things simple, I think I'm going to use the rocker switch without the indicator light.....one less thing to try and figure out 5 years from now when things stop working for whatever reason.  I tested everything indoors in a dimly lit room.....ya know, I originally thought that amber light was an LED but now I'm not so sure....may just be a light pipe utilizing a tiny incandescent bulb, like the bulb for the one nearby to help you find the switch on the dash at night.
Rich
San Diego

    On Thursday, April 2, 2020, 6:27:05 AM PDT, vw_van_fan_Mark <madvws@cox.net> wrote:  
 
 I have 2 used stock switches in my hand.
Testing with a 9 volt battery.
Polarity doesn't matter to either light.
The amber external light only lights when the switch is on and doesn't
care which large pin has power. Switch off, light off.

I'm tempted to open one up.

Mark

>
> You'e working too hard.  What Dennis said -- brown goes to ground and
> gray/blue (not blue/gray) goes to any gray/blue  wire under the dash.  That
> will take care of panel lighting and and the power-on light.  Note that
> power to the switch has to cone on the correct wire or the light will be on
> constantly.
>
> Yrs,
> d
>