I have noticed with my Outlander that when my AC compressor kicks in (which happens almost every minute), my headlights dim slightly.

Is this just my Outlander or are they all like this?

BTW the AC compressor kicks in with a loud clunk sound.

 

all like that.

my ranger does it.

there was a thread around about a year or so ago about the same subject.

 

When the A/C compressor clutch engages, it slows down the serpentine belt for a second which also drives the alternator...so less power is generated for a short amount of time. A clunk when engaging and sounding like a plane taking off when running is normal for the compressor.

 

when the compressor kicks in, doesn't the fans start too? I might be wrong. The fans pull some serious power.

 

We have a winner. The inrush current of the DC motors used in the fans drop the system voltage enough to see the headlights dim. If you watch your idle when the AC clutch engages the pump, they actually rise a 100rpm or so in an effort to overcome the added drag of the AC pump and extra electrical draw. The 100 rpm isn't enough to do it though.