1996 E300D
Is there a way to tell if I need an alternator or the voltage regulator?

On your W210 the voltage regulator is the brush pack. If you meter the + - terminals with the engine running your voltage should be north of 13.6VDC.
The brush pack is the likely suspect and its two screws to remove and not an expensive part. When you seat the brushes back in compress the brushes with a piece of dental floss, insert then pull the floss out and put screws back in.

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15 VW Passat TDI
00 E420
98 E300 DT
97 E420 Donor Car - NEED PARTS? PM ME!
97 S500
97 E300D
86 Holden Jackaroo Turbo D
86 300SDL
(o\|/o)

I just tested my alternator with my smart charger and it read "Alternator OK"
But voltage was down to 11.89. Which is what it was on the battery I just replaced.
I drove it yesterday. Drove it this morning. No check engine light.
I started the car about 6 times and immediately turned it off to check for warning lights.
Check engine light back on.
It was off this morning.

Fully charged batteries should have a voltage reading of +12.6 volts static (no engine running)
With the engine running the battery reading should be 13.6 - 14.5VDC
There is a warning light for alternator on the bottom of the cluster.
What code is present when the check engine light comes on? The check engine light is something else.

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BENZ THERE DONE THAThttp://www.peachparts.com/shopforum/...c/progress.gif
15 VW Passat TDI
00 E420
98 E300 DT
97 E420 Donor Car - NEED PARTS? PM ME!
97 S500
97 E300D
86 Holden Jackaroo Turbo D
86 300SDL
(o\|/o)

I have to read the codes.
I will check the voltage when it is running for higher than 13.6 - 14.5

When the car is running it reads 12.2 volts. This is about 10 minutes after I topped off the charge on the brand new battery.

I tested the alternator using my smart tester and it said ok, but obviously it is not charging

I don't have the code reader. BUt the last time I ran it it said glow plug relay or pre-glow timing relay.
BUt I tested that and it is fine as are my glow plugs.

Check the voltage through the CCU while driving. It should be above 14v. The CCU # will be 0.5v below the reading at the battery so add 0.5v to whatever number u see on the display. You likely need a VR.

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CENSORED due to not family friendly words

the test to isolate those two pieces is called a full field test, on an old Bosch it requires the DF and D/B to be shorted.

It is quite easy on japanese and american alternators, a bit involved on german. I would suggest you stick these terms in google and search for it, that way you can learn the test and its results.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Your smart tester isn't very smart if it thinks 12V is a good charge voltage, or a good voltage of any kind. Might need a visit to the recycling can. New regulator as was said.

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

I have been thinking that years of partying have made my smart tester not so smart.

What is DF and D/B?

I've never done this.
Can I do it with the alternator in the car?

sorry bout that,

DF, B, D and W are pin designations on bosch alternators.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

OK.
So to isolate the alternator for testing I need to put a jumper pins D and B to each other and what do I jumper DF to?
Can I do this on the car?
Do you have a visual?

Then I can put my meter on the positive and the negative terminal of the alternator and read the true output.

Here are the results of my readings and error codes. What do you think?