I have a 97 aurora the park lights seem possesed. I have been told to replace the switch or light module. I am a little leary because the parts are so expensive. Could there be another problem?
Perhaps there is a faulty relay in the box under the hood.
You need to clean the multi function switch contacts(or replace it for $400). The procedure is detailed in the link below to the Aurora boards. Its a common problem.
http://aurorah.proboards47.com/index.cgi?board=1stgen&action=display&thread=1096928040