flashing cabin lights

I have a 98 van and every now and then when I got to start it the parking lights and the over head lights flash on and off for about 45 sec. Then they go off for 15 then start flashing again. This happens for 3 times. If I turn the ignition of and then back on it does the same thing. Other than the flashing lights it runs fine durring that time. Please help me with some type of lead.

Thanks

Bigbartman