Why are my dashboard lights blinking along with my blinker? The dashboard lights also dim when I brake. This just recently started and seems to only occur when I don’t have the headlights on. If the headlights are on, everything seems normal.
Try replacing the front and rear bulbs. I have seen freak occurrences where a bulb filament breaks inside the bulb, shorts to the other filament and causes a feedback in the car circuitry. Or if you have an ohms meter, you can test each bulb by removing it and testing for a crossover short.
Hope this works for you.
I have seen strangeness like this when there was a bad ground on one circuit so the current found a path to ground through an adjacent circuit. The only way I can find these is with a wiring diagram and a vehicle layout. Both of these will be in a Haynes manual for that car, or you can get just the wiring diagram from BBB Industries.
Check the ground straps under hood, particularly attached to a body panel, for corrosion.
More blinker fluid…