Hello friends, question regarding; 93 Civic Hatchback

... when I switch the running lights ON in the car, the rear brake lights are fully lit, and when I apply the brakes, they remain fully lit (as they should be), the only notable change is that all of the dash display lights dim when the brakes are applied. I am not sure where to begin with this. Perhaps I will need an electrical diagram to trouble-shoot. The fuses are all good, under dash/hood. any idea's, or suggestions??

Thanks for your help.
Jeremy

 

Your alternator may be failing.