Flickering lights/A/C whine... deeper problem?

Hi all,

I have a 1998 Toyota Camry with about 126,000 miles on it. I just had to get the computer replaced over the summer (looong story) and small things have been going wrong since then (usually in twos). In August, my clock light went off and lights inside my car (the over head lights that come on when the doors open, etc.) stopped working. Not a huge deal, so I’ve been ignoring it since there weren’t any bigger problems. Today though, two other things happened in quick succession. I noticed a high-pitched whine, very soft, that seemed to be connected to my air conditioning since it stopped whenever my fans were turned off. It raised and lowered in pitch with the acceleration of the engine. Then, a few hours later, I turned my headlights on and noticed that they were flickering, along with all the lights on my dashboard and in my car. When I got home, I turned off the engine and kept the lights on, and they stopped flickering. Then, I turned the engine back on, and they still weren’t flickering on the outside, but still were a bit on the inside. This doesn’t sound like a big deal, I know, but I get nervous when small things happen like this because I don’t know if they’re indicative of a bigger problem. My mechanic isn’t open till Monday, so I just wanted to put this out there and see if anyone has any suggestions for what might be causing this/if this is attached to a larger issue, perhaps related to my new computer, or an electrical issue. Thanks so much for your help!

For the flickering lights, that could be a ground problem. It could be the battery cables/posts or a loose cable between the block and the body.

Check the alternator output for excessive ripple voltage which would be caused by bad diodes inside it. Checking the AC voltage across the battery with a voltmeter while the engine is running will show the story. If the voltage is over .1 volt then you need to replace the alternator.