While driving the break pad wear light went on with sort of half power but had nothing to do with the brake pads. On checking with a voltmeter found no voltage from alternator and the battery very low.
I suspect the battery indicator bulb is burned out so not much help to analyze the problem
I replaced the alternator (what a job) and the charging fault was corrected.
A week went by and the same thing happened again exactly the same as the first incident.
On the 300D turbo 1984 is the voltage regulating done on the alternator or is there a “black box” some place that is causing my problem. I did a search on Alternators and found a lot of guys with the same problem but no definitive answers as to what will cause this problem.
The alternator is a Bosch 65 amp. Water in the battery, clean terminals and belts are tight.
I don’t think the guys at Napa will do a swap for free again.
Thank for any help or ideas

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1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

The voltage regulator is normally built into the alternator on your car, but it can be replaced separately, it looks like this:

http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ423Z0TNEFK&year=1984&make=MB&model=300-DT-001&category=All&part=Voltage+Regulator

Did you buy a new or a rebuilt alternator? If it was a rebuilt, I'm not surprised it failed in a week.

My rebuild is going on six months old... hand rebuilt by a shop in California though....

If your alternator indicator bulb in the dash is burned out, that will cause it to not charge correctly.....

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-Matt

EPA Section 609 Certified MVAC Technician
-----------------
Oil Burner Kartel Member #10

Ahh the smell of Diesel Fuel, it's like coffee in the morning!

My Car:

1982 300SD Turbo Diesel (231,500 miles!) RIP

1984 300SD Turbo Diesel Custom (235,500 mi on driveline.) - On Road!!

www.icsrepair.com

Hopefully you got a good one, I had two rebuilt units fail within a couple of 1000 miles, then I bought a new borsch.

As a professional Technician of 35 years experience I have found that any part that says "Bosch" is the weakest part of any Mercedes.

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Retired
ASE Master Car / Light Truck
ASE Master Medium Heavy Truck
EVT Master Technician Ambulance
EVT Master Technician Fire Apparatus

"Without Fleet The Pride Doesn't Ride"

1983 300SD 609K + still going strong!
1970 Monte Carlo
1994 Ford F150

That one I'll toss you on Can you spell L U C A S?

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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)

Thanks Deerefanatic. I will pull the dash tonight and replace the bulb. Is it different from the other bulbs in the dash? Or a special bulb.
The Gears

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

I pulled the dash and found the bulb for the charging system to be OK.
Do you know where the wires from the alternator terminate? Could there be a broken wire? Can I exite the alternator manually, bypassing the dash?
John

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

borsch alternator??? Sounds Russian

Take it back to NAPA. They stand behind their parts

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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.

LOL, the spell checker didn't help me with that one.

Dash bulp OK. All wires OK. 10.5 volts from dash to Alt. plug with key on.
Feeding 12 volts back to dash will light up the low pad light but not the battrey light. On the wiring diagram it shows a resister and diode between the low pad light and the battrey light line to the alternator.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

I'm having some problems with my alternator now on my 77. Did you replace with an internally or externally regulated alternator? Are you sure the bulbs are not switched around on the dash so you're actually getting the battery light on the brake light? I know I accidently misplaced the seat belt warning bulb in the wrong hole on the left side of the dash on my 85.
I'd also suspect a bad alternator.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Hi Kerry. On the 84 300D the bulbs can't be mixed up as the battery light is larger that the other bulbs, different base. The alternator has a internal regulator that also holds the brush set to contact the slip rings that feeds exciting current to the rotating field. Misplacing a bulb won't change the function of that perticular bulb sosket. Exciting volyage comes through the idiot light to the alternator and from a second source, the low pad light via a resistor and diode to the battery light.

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1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

Take a booster set and connect from battery negative terminal to a clean spot on the block or alternator if possible. There is a small chance you might have ground problems. If the alternator starts to charge you have it. If not you have elminated any possibility of it.

I have been having a heck of a time with my charging system also. My low pad light has never worked since I had the car. Are you telling me that if this light is out, then I don't get a field to the alternator??

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1989 300E
103,500 miles

1982 300SD
Sold but not forgotten