Voltage Regulator Replacement DIY- Its usually not the alternator
 

Its bound to happen, you get the awesome message that convenience functions are disabled! Then hopefully it comes back and all is good. Well it happened to me back and fourth over a period of 2 days, so I knew the battery or alternator was on the way out. Battery tests showed normal, so it was alternator time.

From what I know, the mb alternators seem to be rock solid. Its the damn voltage regulator that goes out. I guess it makes sense, as it is a wear item.

First get one of these....


1 BOSCH_0031546506_S

BOSCH Voltage Regulator NOTE: For cars with BOSCH Alternator.

$41.00
aboveallmotorwerks.com

http://www.eurocharged.com/images/IMG_0118.jpg



I was able to replace this in about 20 minutes without removing the alternator!



Jack the car up on one or both sides and remove the underbelly pan.

Disconnect the battery (just do it) and get under her and take a look!

Find the bottom of the alternator. Remove the black and yellow wire connector.

Also screw off the plastic black cap in the middle.

http://www.eurocharged.com/images/IMG_0105.jpg

Using a Philip's head, remove the screws that hold the cover on.

http://www.eurocharged.com/images/IMG_0110.jpg

you can then use a socket to remove the power lead from the middle.


http://www.eurocharged.com/images/IMG_0105.jpg


Now, the voltage regulator is only held on with a few more Philip's screws. (3)

Remove those, and she will fall (literally) out

http://www.eurocharged.com/images/IMG_0109.jpg

Take a look at the difference and you can see the wear on the leads of old vs new

http://www.eurocharged.com/images/IMG_0112.jpg

http://www.eurocharged.com/images/IMG_0111.jpg

Put the new one back in, using the same process. The smaller screw goes in the bottom corner of the regulator when you get it back on the alternator.

Replace what you took out and you should be good to go!

I have done a few of them for people and have yet to have to replace an alternator

:y

nice DIY

Pretty cool that you can do this without removing the alternator.

31 bucks on parts.com for u cheap skates :)

Nice writeup!

Jake can you do mine when you come down for the mile :)

Nice writeup, Thanks!! Will be doing this soon.

not a problem!

we can even do it at the track. Just bring a socket set and a screwdriver!

Nice Write up.
Thanks

thank you Sir!

Great DIY write up Jake.

Great pics!

Did it matter that it looks like the tabs are different on the 2 regs?? I guess it was not an exact replacement.

i believe those are the leads that wear down and therefore do not make enough contact to be reliable. Thats where changing to a new one solve the problem. I could be wrong.

kind of like brush contacts on an electric motor.

correct! Once they get small enough, they don't make contact and you get the voltage errors!

Top man Loungn.

Really useful infomation,,,,,,,,,,,,,,,,,,,,,,,,, many thanks

another nice DIY to save some $$$. Can we add this to the DIY or sticky it?

Anything we need to know when we reconnect the battery?

Good info!!

Do you have the part number?

not really....just have to reset windows/sunroof as usual

twas at the top ! 0031546506

:y

Did mine last night. Very easy to remove and install... Too bad it did solve my issue... Can anyone point me to the cheapest alternator?

Well at least you used SEARCH and didn't torment us by asking a NEWBY question like "my ESP light came on what do I do now?"

Did you test the battery under the hood? It can also be the cause.

well i changed the alternator and charged up the battery... car started up fine. but after 30 minutes of running.. the battery/alternator display popped back up. so i did a next charge and checked it with a voltmeter, and the voltage did not jump after start.... it stayed at 12.XX volts and kept going down.