Is it normal for your voltage to drop when you are braking? At idle, voltage is ~14.1 V, but when I apply the brake it drops from anywhere between 12.9 - 13.9. As soon as I get off the brake the voltage recovers.

Does any one have any idea why this is happening?

 

your idle goes down a hair too.

1. brake lights need voltage so they use some up.

2. your lower idle spins the alt slower = less voltage.

together = a voltage drop = normal

how are u checking this voltage?

 

across the posts at idle/stop and with one of those lighter-meters.

could this also be an indication of the alternator ready to go south?

thanks