97 Pontiac Sunfire 2.4
I slow down to a stop and my head lights, interior lights and such dim and I get a slight drop in rpm until I come to a complete stop and then everything returns to normal, even while brake is still depressed.
I'm thinking possibly brake light switch or wiring issue drawing too much current possibly?
Smile! All things fade with time...
I think the dimming is caused by the "slight drop in RPM" you experience as you say all is normal once stopped (including the normal RPM). I'd start by checking the battery and alternator. The brake light circuitry doesn't use any more power when slowing as it does when you're stopped (assuming you still have your foot on the brake) as the same lights are still in use in both scenarios.