One problem related to turn signal switch has been reported for the 2003 GMC Envoy. The most recently reported issues are listed below.
No damage to turn signal when I turn on left turn signal sometimes it doesn't work sometimes I can move steering wheel and it will come on for second other times nothing have to try to turn off and on sometimes works sometimes doesn't can not get a good reason why won't work. Have automotive experience at trouble shooting. Also nonsafety issue cruse control on blinker on same switch intermittent working.