1999 Service 4WD warning

Good Day,
Please forgive me as I know this subject has been hashed over several times and I'm grateful for the solution (replace the switch) however, I can't seem to determine the part number for the replacement "shift mode control switch". I've tried searching the web but to no avail. I've seen a few part numbers mentioned but I want to be sure I get the correct one. Can someone tell me the part number or a web site where I can search for the number online? My truck is a 1999 GMC Sierra Z71 4WD and the 4WD switch on the dash is the four button type with the round 4WD Auto button on top then 2W-Hi, 4W-HI and 4W-Lo?
Thanks for your time and assistance.
David

Good Day,
Please forgive me as I know this subject has been hashed over several times and I'm grateful for the solution (replace the switch) however, I can't seem to determine the part number for the replacement "shift mode control switch". I've tried searching the web but to no avail. I've seen a few part numbers mentioned but I want to be sure I get the correct one. Can someone tell me the part number or a web site where I can search for the number online? My truck is a 1999 GMC Sierra Z71 4WD and the 4WD switch on the dash is the four button type with the round 4WD Auto button on top then 2W-Hi, 4W-HI and 4W-Lo?
Thanks for your time and assistance.
David

Part Number is 15709327. I had to replace mine and that is the part number I used. Mine is a 2000 but I am pretty sure the part is the same for 99.

//2000CAYukon