Pulsing lights

So after running about 500 miles on a remanufactured bosch alternator the light have started pulsing. I noticed the serpentine belt looked to be moving on the tensioner more then what I think is normal.

Anyway the clutch on the alternator seems to be fine. I replaced the tensioner thinking it could be getting weak from the old alternator problem and the issue still exists.


Is there something wrong with the alternator?

I have a video of the tensioner while running but I’m not sure how to post it here.

Take a multi meter and check the voltage that is being supplied to the battery while this is happening. It should be a steady 13.8 to an optimum of 14.3. If there is fluctuation in the voltage, the alternator may be defective provided the pulley clutch isn't bad.

I've had a pulsing situation where my fans were cycling on and off(high speed)...the car sat for a week or 2 while I looked for a fan control module...never replaced it and it suddenly stopped

Listen for your fans while you put a voltmeter on it

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Check your ground connections. There are a few under the battery tray and in other locations. Google can probably help find where they are.

I had fluctuating headlights and I tightened all the grounds and it stopped. If I remember correctly, they are usually brown wires leading to a stud attached to the body, transmission, etc...

Mike_04GolfTDI said:

Check your ground connections. There are a few under the battery tray and in other locations. Google can probably help find where they are.

I had fluctuating headlights and I tightened all the grounds and it stopped. If I remember correctly, they are usually brown wires leading to a stud attached to the body, transmission, etc...

Click to expand...

All brown wires are grounds and definitely a check

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Check for alternating current too. You should have < 0.5 volts AC

Thanks everyone.

I have a steady 14.6v at the battery. I will look over all of the grounds.

The pulse seems to be following the serpentine tensioner. It seems to be moving more then normal. I am trying to upload a video somehow. The alternator clutch seems to be working correct. It will lock one direction and free wheel the other. I just replaced the tensioner after this started and have the same results.

Update

Ordered a new alternator from idparts and installed. Car is fine again. One more reason not to buy remanufactured parts from the big parts stores.
Thanks for the help everyone

Glad you got it sorted, thanks for reporting!
Where did it come from and do you know who re-built it?

It came from Oreileys. It was supposedly a remanufactured Bosch. Not sure who rebuilds for them.