Aftermarket Autometer Gauge Dimming with knob or Solder in Resisitor?

I installed two Autometer gauges and cannot get them wired correctly where they dim with my dimmer switch.

They either do the opposite of my dimmer function (dash dim, gauges brighter or dash brighter, gauges dim).

Is there a way to wire these gauges so they dim with the dimmer switch? I currently have them wired to just turn on with my lights, which works... they are just on full bright when I turn my lights on.

Someone mentioned soldering a resistor inline with the gauge positive wire? If that's my only solution for a dimmer gauge, what size resistor should I get that will dim the Autometer gauges around 50% of what they are now?

 

Bump because I don't want to create an account with a random electronics forum asking this question.

Went to Fry's electronics last night and no one could answer the question. Anyone here have an idea?