Intermitent daytime light comes on while headlights on

[97twodortahoe]

So ive got a 97 tahoe with intermitent Headlight issue. When i am driving with my headlights on the daytime running light on my dash will come on intermitently. It comes on for a few minutes then shuts off. It happen two or three times during my 20 min comute to work. Its not triggered by bumps or anything that i can tell. Any Ideas of whats going on??? Is this normal opperation? ive had truck for about a year and havent noticed it until recently. any help would be appreciated! thanks