Alternator going bad?

ASSISTANCE Electrical & Entertainment Systems
1

Hey all, so recently ive noticed my windows are rolling up slowly and my fan seems to lose power when lights are on… so today i get off work and start my car… it barely starts… then i get going and the battery light comes on… then starts flickering… headlights dim… windsheild wipers are slow… etc… I believe it is the alternator, but i want to make sure before i go and buy one and install it… what test do i need to perform with a voltmeter to determine that it is indeed the alternator thats the problem and no ta bad battery or something else…

feedback is greatly appreciated.

-Jeff

2

Do a simple volt-test to see where the battery is at after a night of sitting.

Then, do voltage test on the alternator, with the vehicle on. To do this, do the following:

  • Hook the black/negative lead of the voltmeter to the battery.
  • Hook the red/positive lead to the 10mm stud/nut on the alternator.
  • Start the car.
  • Check Voltage output.

You should be at 13-14V, roughly. Watch the reading for 2-3 min to make sure it stays consistent… A bad alternator can test good at first, but drop dead once it gets warmed up.