2000 buick park lights not working

I have a 2000 Buick Park Avenue and the park lights just quite working.  I have a viper alarm hookeed up and the park lights work when i use the alarm.(arm disarm panic & so on )  They dont work off the switch or the automatic on function of the car.  The dash lights, park lights, & the under the hood light must all be on the same circuit, because they all just quite, but flash as long as the alarm supplies the power.  The grey/black wire on the switch hareness shows 12volt until the switch is pulled to the on postion, then goes dead, nothing.  I replaced the switch and LCM but nothing.  Please help!!

If this happened just after the radio install, unhook the radio and see if your lights begin to work.  If this allows the lights to work again, notice the wire color of the vehicle that you have connected to the ground wire of the aftermarket radio.