Voltage Regulator Replacement DIY- Its usually not the alternator
Junior Member
Joined: Dec 2007
Posts: 45
Likes: 1
From: VA
M3P
Hey guys, attempting to do this right now. Can't seem to get the cover off of the regulator. It's in a tough spot, and I've only been able to find 1 screw holding the cover on. Can someone tell me how many screws hold the cover on? I'm tempted to pry it off, but it seems pretty fragile. This is on an SL55, thanks in advance!!
Junior Member
Joined: Aug 2007
Posts: 47
Likes: 0
From: Santa Monica, CA
2004 SL55
Thanks! I have taken off 1 nut and 1 screw on the cover. Is the other nut the one below the original nut in the middle? My socket won't clear the bolt, though, for shame =( I'll keep at it!
Junior Member
Joined: Dec 2007
Posts: 45
Likes: 1
From: VA
M3P
Yeah you remove the power lead in the middle, then there is another nut under that has to come off also. You'll probably need a deep socket to get it off.
Junior Member
Joined: Aug 2007
Posts: 47
Likes: 0
From: Santa Monica, CA
2004 SL55
I found a deep socket set, ended up being a size 13 for top nut, 14 for bottom nut, and 15 for the nut on the topside.Not sure if the E55 and SL55 are set up exactly the same, but in the end, there were 3 total nuts for the cover + 1 screw.
Here is what I had to work with:
Here is the cover with 2 bolt holes (1 hole uses stacked nuts size 13 and 14) and 1 screw hole.
Here are the VRs (left one new, right one old.. notice the height difference of the brushes):
Hope this works. I ran the car for about 5 minutes and it died though. LOL. I'll try again tomorrow and see if the consumer battery will charge up.
Junior Member
Joined: Aug 2007
Posts: 47
Likes: 0
From: Santa Monica, CA
2004 SL55
LOL, saw this after I posted my pics. They look to be the same setup. Thanks for taking the time to help out, brother
Newbie
Joined: Mar 2012
Posts: 4
Likes: 0
E500
Thank you very much for this DIY, Loungn14. I fixed my flickering lights (headlights, interior lights etc.) on my 2005 E500 (49,000 miles) by replacing the regulator per your instructions. I bought the Bosh part at aboveallmotorwerkz.com and bought a serpentine belt to throw in the trunk at the same time. Price was $42 for the regulator, $35 for the belt and shipping was free.
Member
Joined: Sep 2010
Posts: 119
Likes: 1
From: Arizona
2004 E55 AMG
I just ordered both batteries and a voltage regulator hope this will cure my errors.
Main: Braille Endurance B10049
Backup: Braille No-Weight B14115
VR: Bosch 003-154-65-06 (Don't buy the Huco W0133-1852913 it looked super cheap and much smaller than the Bosch. The STANDARD MOTOR PRODUCTS VR844 looks like the Bosch in every way)
Does anyone have a write up on everything that will need to be recalibrated and how?
Steering Wheel
Windows
Sun Roof
Trunk
???
Main: Braille Endurance B10049
Backup: Braille No-Weight B14115
VR: Bosch 003-154-65-06 (Don't buy the Huco W0133-1852913 it looked super cheap and much smaller than the Bosch. The STANDARD MOTOR PRODUCTS VR844 looks like the Bosch in every way)
Does anyone have a write up on everything that will need to be recalibrated and how?
Steering Wheel
Windows
Sun Roof
Trunk
???
Last edited by AMG903L; Jul 11, 2012 at 11:19 PM.
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MBWorld Fanatic!
Joined: Jan 2009
Posts: 3,182
Likes: 15
From: Northern VA
W211
Well finally got a chance this morning to tackle this. Got everything undone, except for the one screw by itself that is holding the volt reg onto the alternator. I did get the other 2 screws with ease. But the angle/leverage cant get to turn the sole screw by itself. Called it quits for now, since its 93 outside and will head to sears/home depot to find screwdriver philips head that will fit into a socket like some torx heads are. Once this screw is out, i think its smoother sailing for me to remove/replace with new VR.
MBWorld Fanatic!
Joined: Jan 2009
Posts: 3,182
Likes: 15
From: Northern VA
W211
No luck got the car up and running and still have the red battery light. Front aux battery not charging, sitting at 12.6v while rear goes to 14.0...so probably the aux relay cable is bad. Taking it to get diagnosed at my indy shop Benz Elite.
MBWorld Fanatic!
Joined: Jan 2011
Posts: 2,127
Likes: 4
From: Chicagoland
AMG
I am thinking I am going to try this. My lights dim at idle (badly) and I haven't started the car without seeing the "convenience functions disabled . . . " in like 2 years. Now its just getting worse. Before it would still barely hit 14.2, now it barely gets up to 13.3. Hopefully helps, because both battery's are good, but will replace them after this anyways just to be sure.
Super Member
Joined: Jan 2010
Posts: 563
Likes: 31
From: The Villages, Florida
2006 E320 CDI
Eddie and Emil were both MB mechanics. You will be in good hands with them. They should be able to tell you what is wrong. Please keep us informed with the outcome.
Mike T.
Mike T.
MBWorld Fanatic!
Joined: Jan 2009
Posts: 3,182
Likes: 15
From: Northern VA
W211
Update: Replaced the front battery isolator relay and viola!!! No more Red Battery CEL CODE!!!!. New voltage regulator and pretty new battery relay.
Both batteries are getting charged as they should. Thanks again MBworld and Craig (Chawkins) for the relay and BCM. Didnt need the BCM but have it as a backup/spare for either W211s i own.
Both batteries are getting charged as they should. Thanks again MBworld and Craig (Chawkins) for the relay and BCM. Didnt need the BCM but have it as a backup/spare for either W211s i own.
MBWorld Fanatic!
Joined: Feb 2011
Posts: 1,752
Likes: 175
From: London, UK
W212 - E63 AMG
I just attempted this but had to give up halfway 
I've gotten the connector harness thing off, I've removed the black cap and unbolted the 13mm nut. I don't know how to get the main black cover off....there's only one screw, right? I can only make out one screw and its west of the middle as you look at it, right? I've unscrewed it to the point now that it just spins with no resistance...shall I put out on some puffy gloves and pull the thing off, or is there something I've missed somehow?
I've gotten the connector harness thing off, I've removed the black cap and unbolted the 13mm nut. I don't know how to get the main black cover off....there's only one screw, right? I can only make out one screw and its west of the middle as you look at it, right? I've unscrewed it to the point now that it just spins with no resistance...shall I put out on some puffy gloves and pull the thing off, or is there something I've missed somehow?
MBWorld Fanatic!
Joined: Feb 2011
Posts: 1,752
Likes: 175
From: London, UK
W212 - E63 AMG
loungn14, great write up and thanks for making this information available to us.
I changed mine today - voltage at the rear battery with the car on at idle is now a very healthy 14.2v, whereas before it was 13.6-13.8.
Holy brush pack, Batman!
It hasn't gotten rid of my red battery message, but just knowing that this job has been done and my battery is being charged with good voltage makes this money well spent
I changed mine today - voltage at the rear battery with the car on at idle is now a very healthy 14.2v, whereas before it was 13.6-13.8.
Holy brush pack, Batman!
It hasn't gotten rid of my red battery message, but just knowing that this job has been done and my battery is being charged with good voltage makes this money well spent
MBWorld Fanatic!
Joined: Aug 2007
Posts: 2,596
Likes: 5
From: Jacksonville, FL
05 White Pano E55, Cadillac CTS-V
I ordered a voltage regulator, sure hope that is the problem. I went to drive my car right before I was flying out of town (leaving to airport 45 minutes later) and got about 3 minutes from my house and the red battery display came up and then I got the conveniences disabled message.
I freaked out praying I wasn't about to get a car leaving me stranded on the side of the road right before I had to head to the airport (taxi picking me up). I turned around and raced home and about 1 minute before getting back a message conveniences reenabled or something like that came on. I got to the house and hooked my battery charger to the battery in trunk and it said 75% charged. I jumped in the car and switched to the voltage display and started the car and it was reading 13.4 or 13.5, after this I just let the battery charge for 30 minutes on charger then had to leave to go out of town for 3 weeks so no further investigation.
Voltage regulator should be sitting at the house waiting for me and I really hope it is the fix. Both batteries were replaced about 2 years ago so they aren't super old but not new either. Then I guess there is the battery control module as another possible culprit, but praying it is the voltage regulator even though the previous owner of the car said they changed it. They said they did a lot of things and I really have no way of knowing for sure though (no receipts).
I freaked out praying I wasn't about to get a car leaving me stranded on the side of the road right before I had to head to the airport (taxi picking me up). I turned around and raced home and about 1 minute before getting back a message conveniences reenabled or something like that came on. I got to the house and hooked my battery charger to the battery in trunk and it said 75% charged. I jumped in the car and switched to the voltage display and started the car and it was reading 13.4 or 13.5, after this I just let the battery charge for 30 minutes on charger then had to leave to go out of town for 3 weeks so no further investigation.
Voltage regulator should be sitting at the house waiting for me and I really hope it is the fix. Both batteries were replaced about 2 years ago so they aren't super old but not new either. Then I guess there is the battery control module as another possible culprit, but praying it is the voltage regulator even though the previous owner of the car said they changed it. They said they did a lot of things and I really have no way of knowing for sure though (no receipts).
Last edited by urbamworm; Dec 15, 2012 at 02:18 PM.
MBWorld Fanatic!
Joined: Feb 2011
Posts: 1,752
Likes: 175
From: London, UK
W212 - E63 AMG
I hope it gets solved for you.
It will probably help raise the voltage, so we should probably all consider it as good maintenance to do, but my money is on the aux battery relay being the main culprit. It should be on my car anyway...
p.s. your youtube video's are epic!
It will probably help raise the voltage, so we should probably all consider it as good maintenance to do, but my money is on the aux battery relay being the main culprit. It should be on my car anyway...
p.s. your youtube video's are epic!
Junior Member
Joined: Jul 2011
Posts: 46
Likes: 0
From: Orlando
W211 E55 AMG Kompressor
Help!!!!
Hello everyone, can someone please provide some feedback on this tread, last night while idling my E55 in the garage I smelled a faint burning scent, popped the hood and could not find nor describe the source of this burning smell, however, after checking the forum on the matter it's come to my attention that the alternator/voltage regulator could be on it's way out, convienience message comes on and off now so i know there is low voltage (11.1v) sometimes a bit less, here's my question,,, if, it is the regulator thats bad, would I still get the burning smell???? Or is the burning smell a clear sign that the alternator itself is toasted internally....feedback please!!!!!!!
Hello everyone, can someone please provide some feedback on this tread, last night while idling my E55 in the garage I smelled a faint burning scent, popped the hood and could not find nor describe the source of this burning smell, however, after checking the forum on the matter it's come to my attention that the alternator/voltage regulator could be on it's way out, convienience message comes on and off now so i know there is low voltage (11.1v) sometimes a bit less, here's my question,,, if, it is the regulator thats bad, would I still get the burning smell???? Or is the burning smell a clear sign that the alternator itself is toasted internally....feedback please!!!!!!!
MBWorld Fanatic!
Joined: Aug 2007
Posts: 2,596
Likes: 5
From: Jacksonville, FL
05 White Pano E55, Cadillac CTS-V
The voltage regulator only has those metal prongs that come in to contact with something inside the alternator. There is no burning smell, they just wear and don't contact anymore causing different readings. I have never personally smelt an alternator either for that matter when they were bad, they would just quit or make noise. I suppose something could burn up inside of it though.
