00 Lasabre Driving lights

Have the auto daytime lights,,but only the regular lights are on all the time,,yes the switch is off,,I had heard of this before like there is a relay some place for the auto runnig lights to come on at night. Could somebody tell me where this is?? could it be under the seat in the back next to the batt. ? and also the name of this relay?? I have the book for the car but like it dont realy tell witch one it could be..Thanks