There's no control to dim the lights but the solution is simple.  Visit a home or auto tint business and do a little dumpster diving.  A tiny scrap of tint is all you need.  Apply it to the front of the router and you're good to go.  Need it darker?  Apply a second layer or use a different level of tint.
If there's not a window tint business near you, the plastic film is available in strips at most any auto supply store.
Cheers 
