relay flasher problem

[keg]

I have a 2006 Chevy 2500. When I turn on the key you can hear a clicking noise and the dash lights pulse with the clicking, also the parking, tail lights will and clearance lights will flash off and on. If you turn on the parking and/or headlights the lights stop going on and off, but the relay clicking noise continues. The clicking continues for around 2 minutes then stops and everything works fine. But if you turn off the key and turn it back on the relay clicking starts again, the turn signals and emergency flasher work OK when it is clicking. When the lights are off the parking light relay is pulsing, when the parking lights are turned on the relay stops. but the clicking noise continues, sounds like a relay or flasher