Here is the text from one of my earlier posts that includes the links for the ignition switch diagnosis and replacement:
I recently fixed these same issues on my '02 GTP.
My HVAC controls, DRL, DIC, HUD all were acting flaky.
The ignition switch had to be replaced.
I tried the bypass first, hoping to save the cost and effort of replacing the switch assembly, but the bypass only worked for a few start cycles. The ignition switch contacts were badly scorched/burned.
Use this diagnostic process to verify that it is the switch: Sparky's Answers: 2002 Pontiac Grand Prix Blower Inoperative, Erratic When I checked mine, I found 0 volts at the HVAC/DIC fuse.
Excellent write-up on switch replacement procedure here:Sparky's Answers: 2002 Pontiac Grand Prix, Changing The Ignition Switch
The best, bullet-proof solution would be to replace the switch AND install the bypass with the new switch. If you do this, the new switch will never see the high current loads and it should last indefinitely.
Switches are available from any auto supply. I actually got the best price on a Delco unit. Good luck!
Joe
