I recently picked up a 2007 Fit (sport). This morning, on a cold start, I noticed that my electrical system was acting weird. All of my lights, exterior and interior, were pulsing. I have a cheap Bluetooth adapter for audio that measures voltage; this was showing 12-15.1 volts.

Is my alternator failing? Anyone have any good writeups on replacing an alternator?

 

It could be the alternator. If you do replace the alternator, it is a huge bitch on the GD3. How I do it:

jack up car on jackstands, remove right front wheel, and fender liner to see the serpentine belt and pulleys.

from underneath, using an impact wrench and many extensions (for a total of about 24 inches of extension), you can blast off the alternator bolt. I usually unhook the coolant hose to get around it.

unhook and remove ABS system connector.

undo locknut. Back off the alternator belt tension bolt all the way.

remove EGR valve and EGR studs. You can use two nuts jammed against each other on the studs to unscrew them

slip off belt, take out alternator bolt you blasted off with an impact, carefully remove alternator. Replace and lightly thread in alternator bolt to hold new alternator. Slipping the belt back on is a huge pain.

adjust belt tension with the bolt. Tighten belt tension bolt locknut. Reinstall, ABS sensor connector. Torque main alternator bolt (again, using a bunch of extensions from underneath for access. Torque is about 32 ft-lb if I recall. Reinstall EGR studs and valve.