2003 auto lights

My 2003 gm ls started flashing the lights, dash lights went from dim to bright constantly. I turned the lights from auto to manual off, problem continued. turned lights on manual and headlights worked fine but dash continued to flicker from dim to bright. Pulled all fuses to system to check, all good but when I replaced them the problem went away. obviously something that is always hot reset when i disconnected the fuse.
Any ideas would really be appreciated.

I have a 2004 MGM and the headlights work intermittantly. The pkg lights work fine but just the headlights come on and go off whenever they feel like it. I can hear a click everytime thet do this so I know it's a relay. Does anyone know exactly which one or where this problem is b-4 I rip out the dash and start looking??? Help

A year ago, my 03 MGM headlights would go out after being on for 10-20 minutes. The only way to drive at night was to hold the turn signal stick in. This flashes the brights.

After pulling the dash, inspecting the switch and all fuses and relays, I was stymied. Finally found a post somewhere that pinpointed the problem to a faulty control box that is below the steering wheel on the driver's foot well.

I checked around and found that the repacement is expensive. I managed to get the dealer to give me a discount, but it still set me back $350.

It fixed the problem, though and I've had no troubles for a year now. The dealer parts guy told me that cab drivers are a frequent customer fro this part, but he assured me he only has seen one-time buyers as the new part has been reengineered to resolve the issue with the original box. We'll see I guess.