Headlights turn off when A/C turned on.

[Assassin85]

The Wife and I have an 02 GT. When the A/C switch is on 1, at low speed no air comes through, at Interstate speed you can feel air come through that is cold but does not seem to move at the speed of the 1 setting. On settings 2 through 4, 95% of the time you feel no air at high or low speed. The A/C motor does not even seem to turn on, no obvious fan or compressor noise. At the same time, when the switch is on 2 through 4 and the A/C is not working my headlights also will not turn on. (Discovered that on a 2A.M. grocery store run.) The headlight issue only arises however when the light switch is set to off (all the way to the left). If I set the light switch to on (all the way to the right) the headlights will stay on weather the A/C is working or not. When the A/C switch is set to 5, sometimes there is a delay before the A/C starts working but will work at level 5 efficiently 99% of the time. I should also note that on settings 2 through 4, the indicator light above the A/C button does not light up no matter how many times I push it but does light up when the switch is on 1 and 5. I can also hear the clicking sound of the motor, fans, or compressor when I change it to any setting 1 through 5 weather the A/C is working or not at that time.

[johneric]

I had the same issue with my 98 GTP, from reading other threads I learned that it was the ignition wiring harness running down the steering column. I had it changed
last week and now everything works fine. Before changing the harness the a/c or heat would only work on speed #5. Any other speed would not work and shut my headlights and the display on the dash off.

Hope this helps.

[Paulk501]

same problem here. i swaped out the ignition stwich and all worked fine again

[gsal86]

I have the same problems with my car and am looking to swap out the ignition switch before it gets cold. Is this a big undertaking? I had a mechanic tell me they would do it for around 400. Is it just the switch that needs to be replaced or the entire electrical harness?

[Paulk501]

its not a $400 job but its not the easiest ether. the hardest part is getting the shroud off from around the steering wheel. then take off the bottom part of the dash so you have access. also you will need to remove the key cylinder.

the switch and wiring harness is all one part. its a switch with about 2 feet of wire attached. all the wires plug into a connector under the dash.

switch looks like this



check out.
http://www.automotiveforums.com/vbul...d.php?t=653340

http://www.ehow.com/how_2181625_swit...rand-prix.html

[gsal86]

Thanks for the help! I will be trying it in the next few weeks. It looks a lot less complicated with these instructions verses my Haynes manual.