It seems every time I turn on my ac there is a slight chirping sound going on very faintly lately and I just replace my alternator and the electrical problems are coming back again after a month. Just this morning I would start the car and it barely started like the battery was dieing and it's new. Later after work the radio would cut out and I think the the service, abs, or tracs came on briefly since it flash so fast I couldn't tell what it was. After I got home I turned the car off and move the key into position II and nothing would light up. Had to do it a couple times and then it would show the lights. I did check the belt for glazing or cracks, but it's fine.

 

could be a belt tensioner thats going bad. Check that first, and replace it if it's bad. I'd also spend the 20 bucks and get the replacement serpentine belt.

 

It could be just the belt, but I would replace the tensioner also just to be sure. Them normally go out around the same time anyway.

 

I just had the AC tensioner changed on my 05 S40 but I still have a chirping noise thats rarther loud. Could it be bas belts? I've noticed that my S40 has two belts. One is AC Compressor to Alternator. I have to look at the other one what it's connected to.

I thought the chirping was more like a metal noise but the mechanic mentioned that it is most probably the belts. Could that be true?

 

You could be hearing the A/C clutch chirping from too large of a gap or scorched bearing.
Search for the ever-popular bread clip adjustment I've heard so much about.
Ed

 

I just had the compressor changed so I'm eliminating the bearing possibility.

I'm thinking probably misalignment of pulleys?

OR

Bad belts

OR

A combination of both

My belts seem pretty shiny (mechanic said shiny is not good) and I should probably try fixing the belt with the nice Dayco one.

 

I have never heard of a belt causing a problem. Pullies, rollers, and other items may damage a belt, but not the belt itself. It's just a piece of rubber. A victum in the path. They get old, crack, and break, not cause problems.

Take the belt off, takes about 15 seconds, then check the items in the path. How smooth does items turn? If the belt is old and maybe has been contaminated with some kind of fluid like oil or something, maybe it needs replaced. Other than that, it's a componet in the path.