Intermittent Automatic Headlights

1. At night, the automatic headlights do not activate or turn off for no reason, requiring the manual switch to be used. They may re-activate for short periods while in manual mode. (the shift position indicator light brightens during the malfunction and dims when operating normally). The manual switch can then be turned off and they will stay on for just a few minutes but then go off again.

2. The A/C does the same thing, day or night.

3. The vent fan, with or without the A/C does the same thing.

4. The Electrochromatic Dimming Rearview Mirror also fails during these periods.
All other electrical functions are OK.

These are intermittent problems that just started and seem to happen at the same times.

Are they related in some way through an electronic chip or switch of some sort?

Solution . . . . .

The Buick dealer found the ignition switch to be faulty. Replacemnt corrected all of the above items. $125 Parts and $200 Labor. Not cheap but it works now.

I'm having the same problem with my 98 Regal. My problem has become more than intermittent - it's to the point now where these items only work some of the time. When the automatic lights aren't working, the cruise control drops out and the fan won't run (a/c on or off, heat on or off). It's getting to be a cold ride to work these days. I'm looking for some ideas on what to repair/replace. There must be a module that controls all these items...

I am having the exact same problems. It started when the battery was replaced. I have noticed that the headlights will operate correctly if the fan switch is in the off. position. The fan will work on High. If the fan switch is in any position other than off, Auto headlights, rear defrost and rearview dimmer will not work. I had the battery disconnected for a couple of days when I replaced the starter and when I reconnected it, everything worked fine...... for a couple of days. Anybody out there that can help track down the problem? One other thing, the left turn signal acts as if there is a burned out bulb. the bulbs are fine, the front flashes and the side marker turns on. The rear does not flash, however both brake lights work. I hate electrical problems!