97 Volvo 850 - I usually keep the switch for my headlights on the Daytime Running Light position; last night I cranked the vehicle and I noticed that there were no headlights. Thought I had accidentally turned the switch, but that wasn't the case. Turned the car off, restarted it, and lights came on. Okay ... So I drove to destination, went into the store, came out and cranked car again .. no headlights. Other interior lighting worked, radio worked, door locks, etc. all worked. Stepped on the brakes and I could see from the reflection behind me that both headlights and brake lights were not operating. Turned car off, checked fuses (all looked good), cranked car again and headlights and brake lights came on. I recently lifted the dash board to install an upgraded instrument cluster, and wonder if I may have not connected something or possibly slightly disconnected some cable connector. But before I start pulling dash board up again and checking instrument cluster, thought I'd check to see if anyone has experienced anything similar to this, or where I might best spend my time diagnosing. Thanks for your responses in advance.