89' 300SE w126

cluster lights went out in the car the other day. I had replaced the dimmer switch before so i was like no big, I'll just order another. So i go to the Stealership and pay $88 and install it. Still no lights. So i browse around and hear about a red fuse type thing. I pull cluster again and check it out. looks ok but then again with fuses you never know. I did install a new head unit a while ago and wanted to re-install the becker and plugged in the old becker to the power harness and antenna to see if it still worked then plugged in the new sony H/u