SL/R230: voltage
Thread Starter
Member
Joined: Apr 2012
Posts: 179
Likes: 4
Sl55 2003
voltage
Anyone know how to check what the voltage coming out of the alternator is.
I got the xentry system today with the car on my batt goes from 14v to 10 after some time. then i get votage error.
I bought a new regulator deciding weather to install or is it something else.
I got the xentry system today with the car on my batt goes from 14v to 10 after some time. then i get votage error.
I bought a new regulator deciding weather to install or is it something else.
Member
Joined: Jun 2019
Posts: 200
Likes: 26
2005 R230 SL-500 / 2017 E300
Conet the + and - leads of your volt meter to the + and - posts of the battery, Have someone start the engine while you are watching the volt meter. the voltage should increase when the engine starts indicating that the alternator is charging the battery. If the voltage just decreases then your alternator is not charging the battery.
You might want to try this on another car that is working properly to see what it should look like.
Mike.
You might want to try this on another car that is working properly to see what it should look like.
Mike.
MBWorld Fanatic!
Joined: Mar 2008
Posts: 1,232
Likes: 168
From: Glasgow, Scotland, UK
SL 350 R230 (3.7L with AMG Speedshift autobox)
With engine on, charging voltage should be around 14.1V regardless of load (lights, heater) the voltage regulator maintains the Volts by definition.
Just stick a multimeter on your rear battery and start the engine.
Member
Joined: Jun 2019
Posts: 200
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2005 R230 SL-500 / 2017 E300
In the old days of mechanical regulators you would just connect the field terminal of the alternator to ground which would send the alternator into full charging output increasing voltage at the battery. If grounding the field terminal does not raise voltage then the alternator has a problem. Even if you could find the field terminal on your R230 alternator I would hesitate to strap it to ground for fear of damaging a sensitive electronic component.
In any case the regulator is probably inside the alternator case so the alternator will need to be removed for repair.
This may help
https://mbworld.org/forums/sl-class-...lator-diy.html
Mike.
In any case the regulator is probably inside the alternator case so the alternator will need to be removed for repair.
This may help
https://mbworld.org/forums/sl-class-...lator-diy.html
Mike.
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Member
Joined: Jun 2019
Posts: 200
Likes: 26
2005 R230 SL-500 / 2017 E300
Use a long handled wrench and instead of pulling on the wrench handle, rap the handle with a hammer. This will often break a stuck screw loose. Heating up the engine might also help.
I just did some reading online and I learned that the regulator has contact brushes that wear with time so it's a good idea to change it as a matter of course after 100k miles or so.
Mike.
I just did some reading online and I learned that the regulator has contact brushes that wear with time so it's a good idea to change it as a matter of course after 100k miles or so.
Mike.
Thread Starter
Member
Joined: Apr 2012
Posts: 179
Likes: 4
Sl55 2003
Anyone on long island that is handy that can help switch regulator on alternator , I have bottom 2 screw out but the final one is stuck. Im on exit 39. thank you
MBWorld Fanatic!
Joined: Mar 2008
Posts: 1,232
Likes: 168
From: Glasgow, Scotland, UK
SL 350 R230 (3.7L with AMG Speedshift autobox)
otherwise use an easyout tool
You may find once you have the regulator off, the brushes have just worn ?
Member
Joined: Jun 2019
Posts: 200
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2005 R230 SL-500 / 2017 E300
If the alternator were on the workbench you could break the plastic body of the regulator exposing the screw shank so that you could use a vise griip pliers to remove it.
Mike.
EDIT - Also ii the alternator were on the bench I'll bet that you would be able to remove the screw with a screwdriver.
Mike.
EDIT - Also ii the alternator were on the bench I'll bet that you would be able to remove the screw with a screwdriver.
Last edited by mikefamig; Sep 25, 2019 at 11:35 AM.
