Headlights and A/C on the SAME circuit??

I have a 1999 Pontiac Grand Prix Se. I have been having problems with my a/c lately...its a weird one though. The reason I say that is because as long as the a/c is turned to the "off" position evreything is working fine. But, as soon as I turn the a/c to the "on" position the headlights will turn off and I have to manually turn them back on. For I while I was procrastinating taking it to the mechanic shop because the a/c would still work. (Oh, by the way, it would only work on the "High" position.) Well anyways, I was on my way home from work that other day and it was blowing cold air and then all of a sudden it stopped blowing all together. Its weird because I am still having the same problems with the headlights being turned off when I try to put the a/c to the "on" position. My friend said that its because they are on the same circuit....does that sound right? Any ideas what may be happening. PLease help...its HOT!!!(hahaha)

I have a 1999 Pontiac Grand Prix Se. I have been having problems with my a/c lately...its a weird one though. The reason I say that is because as long as the a/c is turned to the "off" position evreything is working fine. But, as soon as I turn the a/c to the "on" position the headlights will turn off and I have to manually turn them back on. For I while I was procrastinating taking it to the mechanic shop because the a/c would still work. (Oh, by the way, it would only work on the "High" position.) Well anyways, I was on my way home from work that other day and it was blowing cold air and then all of a sudden it stopped blowing all together. Its weird because I am still having the same problems with the headlights being turned off when I try to put the a/c to the "on" position. My friend said that its because they are on the same circuit....does that sound right? Any ideas what may be happening. PLease help...its HOT!!!(hahaha)
:banghead: iam having the same problems on my 97 gp gtx,has any one found a fix? HELPPPPPPPPPPPPPPPP

Ignition switch harness is the culpret..it's not a un-common problem with our Grand Prix's.

Check the following posts:

http://www.automotiveforums.com/vbulletin/showthread.php?p=2082872#post2082872

(Above is general info)

http://www.automotiveforums.com/vbulletin/showthread.php?p=2279687&highlight=replacing+ignition+switch+harness#post22 79687

(step by step directions)

http://www.automotiveforums.com/vbulletin/showthread.php?t=386768&highlight=ignition+switch+harness

(Part Numbers - first one is ISwitch Harness)