Double check all of your fuses, your courtesy lights and then double check all of your grounds. GM/Pontiac wired up the courtesy lights hot on to two different circiuts, when you blow a fuse, you can create a back feed flow of electricity. My radio would lose its presets when I opened the door, brake warning light would go on when I honked my horn and etc.
Although this may not specifically apply in your case, the understanding of this condition will help you in your diagnostics. I went batty while trouble shooting the electrical without this little tibbit of info, hopefully I saved you from some grief.
Oh yeah, how about a little link,,,
http://www.fieros.de/en/articles/screwup.html------------------
jetman
Silver 86 SE 2M6 4-speed, with "check wallet light"
