[IS200] Weird problem - kinda dim and uneven cluster and AC panel lights

I've noticed that my cluster lights are pretty weak. The dimmer works fine. I changed them to some quality LEDs with no difference. And the backlightning is uneven. For instance zero in the 120km/h mark in underlit but only half way, and it goes like that til 140, and then it's kinda good again. It almost looks like the clockboard itself is dirty in places, but it's never been touched so I don't know.