Electrical Problem with Voltage Spikes. Video

Ive been having this electrical beeping problem on start up. I finally got my dads scan gauge in my car. Here is a video of the voltage spikes and the dash esp, abs, and break lights flickers as well as all the interior lights.
http://www.youtube.com/watch?v=d_0tBEymTg8
Is my alternator bad? What could be causing this?
Thanks Guys

That 16v spike is too high; could be a faulty voltage regulator; but I'm just guessing.

thanks you, Im pretty new to alternators and voltage regulators any more advice guys would be amazing

thank you

The SG is too slow. Can you check the voltage at the output terminal on the generator? It's the one with the large black wire connected to it.

Can you check for voltage across any of the main fuse links, and for voltage between the battery (-) and the engine block? Make sure you use clean test points.

Basic regulator circuit test - the "battery" lamp will illuminate when the engine isn't running. If the lamp flickers during running or extinguishes when the engine is off, the regulator is probably bad.

Thanks for your response! Whats SG? Do you mean check the output on the alternator terminal?

Scan Gauge, and yes.

makos101 said:

Thanks for your response! Whats SG? Do you mean check the output on the alternator terminal?

Click to expand...

SG is your Scan Gage. Yes, see if you can test the voltage right at the battery terminals with a decent quality digital voltmeter. If it turns out to be the voltage regulator I believe they can be replaced with the alternator installed in the car. They aren't too expensive either:

http://www.ecstuning.com/Volkswagen-Jetta_III--VR6_12v/Search/Voltage_Regulator/ES2792/


That link mostly supplied for visual refference. Check the model number/type of your alternator and verify fitment before you order. I have seen good quality german made parts for reasonable prices on Ebay as well.

Here is what the voltage regulator looks like installed on the alternator:

http://www.justanswer.com/vw-volkswagen/1mxbr-replace-alternator-2002-vw-jetta-gls.html

..

I just looked at a junk alternator I had laying around to see what it takes to get to the voltage regulator. Once the battery cable, and control harness is removed from the alternator all that is needed is a 13mm, 15mm, and a phillips screwdriver. Once the plastic alternator shroud piece(also contains some unknown circuitry) is removed by taking off the 13mm not, and 15mm nut, the voltage regulator can be accessed by removing the phillips screws. I am reasonably sure this can be done in the car. The coolant inlet pipe/flange may need to be removed however.

Hey guys thanks for all the advice. Ive tried a few voltage tests and cleaned the alternator ground.

When driving the voltage on the Scan gauge stay at 14 volts. But when idle the voltage drops to 13.5. Is 13.5 low?


Does this sound like it could be the pulley, alternator, and regulator? The car has 170k miles and they have never been replaced.

Thanks for all the helpful advice.

13.5 does not seem too low for this time of year. I have a volt meter which is pretty accurate that is plugged into my cig. lighter and it too reads ~ 14v while driving and just one or two tenths lower at idle. I have no accessories ON and my DRL's are OFF.

Hey guys I replaced the alternator yesterday. So far there has been no beeping/flashing dashboard lights and the voltage has been steady from 13.7-14.0. There also has been no voltage spikes that go down to 12.5 and then up to 15 when the car is in idle and the lights don't dim when I touch the breaks.

On examining the old alternator the pulley spins freely, there is nothing touching on the inside of the old alternator. When i spun the new rebuild alternator you could feel a light brushing inside.