300SDL new alternator - PeachParts Mercedes-Benz Forum

lt1fire · #1 06-11-2012, 06:31 PM

Could be needing a new alt. for the SDL. Might just be the voltage regulator but haven't gotten around to checking it out. I know these alts suck in how much charging they can do. I read somewhere that a ML430 alt that throws out 150 amps will fit right in there perfectly and hook right up.... is this true??? If not what is a good plug and play option.

Diesel911 · #2 06-11-2012, 07:36 PM

Good lord a rebuilt Bosch one at the place I looked is $177. AL65X; 70amp

You did not give any testing Voltage information or even say if your Charging Light was coming on?

If the Alternator issues on your year and Model are the same as the 123s it could be a good idea to see if it is the Alternator/Regulator is actually the problem or some wiring or even a Battery issue before swapping Alternators to a higher amp one.

lt1fire · #3 06-11-2012, 08:38 PM

Sorry..... charging light is not coming on at all (may or may not work) Not the battery..... Battery went dead last week, got a new one on thursday, new battery is dead again today.... car runs off of a jump.

Could be the regulator, haven't pulled it to check yet. But eventually i'll want to get a more powerful alt anyway so it will be usefull to know.

layback40 · #4 06-11-2012, 08:57 PM

Quote:

Originally Posted by lt1fire

Sorry..... charging light is not coming on at all (may or may not work) Not the battery..... Battery went dead last week, got a new one on thursday, new battery is dead again today.... car runs off of a jump.

Could be the regulator, haven't pulled it to check yet. But eventually i'll want to get a more powerful alt anyway so it will be usefull to know.

If idiot light does not come on at start then alt will not charge.
Test the globe, probably blown.
50c globe & you have replaced the battery & looking at alt replacement !

lt1fire · #5 06-11-2012, 09:03 PM

Globe??? Bulb maybe. Battery was drained so bad it had a dead cell and was replaced under warranty so no harm there. Gotta love 8 year warranties.

Diesel911 · #6 06-11-2012, 11:19 PM

like layback40 said when you first turn your Key all of your Warning/idiot lights should light up. That is the check to see if the Bulb is burned out.

The little Charging Light Bulb is needed in the Circuit because that little bit of resistance that the Bulb provides is needed to excite the Alternator so it will start charging.

I have read 2 Articles and one said the Bulb needs to be a least 2 watts that onther said it needs to be a 3 watt Bulb.

lt1fire · #7 06-11-2012, 11:31 PM

hmmm i'll check that in the a.m.

lt1fire · #8 06-12-2012, 09:34 AM

Quote:

Originally Posted by Diesel911

like layback40 said when you first turn your Key all of your Warning/idiot lights should light up. That is the check to see if the Bulb is burned out.

The little Charging Light Bulb is needed in the Circuit because that little bit of resistance that the Bulb provides is needed to excite the Alternator so it will start charging.

I have read 2 Articles and one said the Bulb needs to be a least 2 watts that onther said it needs to be a 3 watt Bulb.

only the ones on the right side of my steering wheel light up.....

so is there a good thread on how to remove the cluster to get to them.??

lt1fire · #9 06-12-2012, 06:37 PM

ok pulled the gauge cluster and found I had no E-brake light... replaced that with the light the parts store gave me for the charging lamp but it was the wrong side..... now when I turn my key I get the e-brake light, and a few on the right side of the steering wheel. I also changed the charging light with the one from the bulbs that illuminate the gauges but the charging light still will not come on when I turn the key.

lt1fire · #10 06-12-2012, 07:02 PM

pulled the voltage reg..... the carbon stacks are quite a bit shorter than the ones in diesel giants install guide
Mercedes Voltage Regulator Install

Might get a new one for the heck of it right now ($26 can't go wrong)..... still want to get a higher output alt down the line

Question is though would a bad reg cause the light to not come on??

Hit Man X · #11 06-12-2012, 07:22 PM

Yes, you can upgrade the alt easily... same with M103 cars.

I have a 143A on my car, think it came off a W140 that was powered by an M119. Obviously the cable needs to be upgraded also.

Works great along with afterglow.

compu_85 · #12 06-12-2012, 07:32 PM

I have a 115A on my car.. works great

My car had thicker cabling so I didn't need to upgrade anything besides the alt

-J

lt1fire · #13 06-12-2012, 09:26 PM

Found this in another thread

"Aside from the not charging, I was most bothered by the fact that the idiot light on the instument cluster (charge indicator lamp) did not light up when the ignition was keyed prior to starting. I pulled the instrument cluster and determined that the bulb was functional. I then tested the continuity of the thin blue wire that runs from the plug on the alternator (the other two big red ones run to the starter) to the big round plug on the fuel/temp/oil pressure gauge on the back of the instrument panel (pin #6 on my car), and sure enough there was an internal break. So, I spliced in a new wire from the alternator to the idiot light and viola, light works = charging system works."

Thinking this might be my problem.......... where is this blue wire exactly..... sorry I will be the first to admit that any kind of electrically problems confuse the hell out of me.....

lt1fire · #14 07-26-2012, 03:10 PM

Finally got around to fixing this.
Bought a ML430 150A alt off of ebay for $65 pulled the old one made new wires. Had to swap the pulleys on the old one to the new one.
2 4G and one 10G to replace the old ones.... 44in for all of them. Put it all back together and it all works fine now. Warning light comes on, in the dash, charging tests out fine, even pulled the battery cables to make sure the lights come on from just the alt and it worked fine.