[denis0625]

So I've got a w210 e280 4 matic from 98. Ive been reading around and came to the conclusion that one of the two needs to be replaced in my car. Is there a way to narrow it down with out taking the whole alternator out?



Heres what I've noticed...


Car starts no error lights, no problems.Even if i leave the car running for a long period of time no errors will appear. As soon as i rev/start to move, ETS/ABS, traction control lights pop up.

Also, and this is completely random some of the electronics stop working. For example, one day everything will work perfectly, the next day, the front right windows and mirror will not work (electric). Then it will work alone after some time. Sometimes its after leaving the car alone for 10 mins, and sometimes its after several days. It is completely random! Its not just the right side, some times its the left side too, and sometimes both sides, and sometimes i won't be able to lock the car with the key because the whole left door won't work (electric seats, left mirror, etc)!


any suggestions or ideas would be greatly appreciated !

 

[Musikmann]

The first thing I'd do is check the battery voltage output. It's pretty easy using the climate control, the steps are in the stickies.

 

[EFSiR]

after that, I'd check all ground connections and since you mentioned door issues, wire harness for power mirrors to make sure you're not shorting.

 

[Kajtek1]

Partial electrical system shut down can't be related to charging system.
Look for overheated electrical connectors. Also the cable under driver feet is know to create issues.

 

[Check Codes]

My guess would be the VR. What you're describing is typical symptoms in this generation of Benz when overcharging is present. That it happens as soon as you hit the gas increases the likelihood that it's the VR.

At least if it were my car that's where I'd start. Of course I'd probably connect a voltmeter to the output of the alternator and watch it as I started the car, let it idle and briefly revved it up a bit (no more than 3,000 RPM).

Good luck.

 

[Musikmann]

Partial electrical system shut down can't be related to charging system...

Agreed I was focusing more on the warning lights.

 

[Check Codes]

Partial electrical system shut down can't be related to charging system.
Look for overheated electrical connectors. Also the cable under driver feet is know to create issues.

Actually, what the OP reports has been noted in cases of overcharging.

 

[denis0625]

My guess would be the VR. What you're describing is typical symptoms in this generation of Benz when overcharging is present. That it happens as soon as you hit the gas increases the likelihood that it's the VR.

At least if it were my car that's where I'd start. Of course I'd probably connect a voltmeter to the output of the alternator and watch it as I started the car, let it idle and briefly revved it up a bit (no more than 3,000 RPM).

Good luck.

that is right, as soon as i hit the gas all the errors appear. Will it work if i connect a voltmeter to the battery under the back seat? what are the "ideal" numbers i should be seeing?

 

[denis0625]

Partial electrical system shut down can't be related to charging system.
Look for overheated electrical connectors. Also the cable under driver feet is know to create issues.

My mechanic said he went through all the wires and said he hasn't seen any problems regarding the wiring. any other suggestions?

 

[Check Codes]

that is right, as soon as i hit the gas all the errors appear. Will it work if i connect a voltmeter to the battery under the back seat? what are the "ideal" numbers i should be seeing?

While there is likely little difference, since you want to see alternator output, it's best to tie in at the alternator. Red clip to the big lug on the back (slip the rubber cover off) and black to any exposed metal.

I don't have specs in front of me, but 13.5-14.5 is normal with the engine running depending on battery state. You might see a little less than that at idle with a fully-charged battery, maybe a tiny bit more with heavy loads, 2,500+ rpm, a low battery, and frigid temps.

Alternatively (no pun intended), you could just disconnect the battery, yank the alternator and take it to a parts store (or rebuilder if there is one near you) and have it tested. They will put it on a bench tester and can tell you whether it's under or over charging; if the former, they can tell you if it's the alternator or regulator, and if the latter, it's always the regulator.

Good luck.

 

[Check Codes]

Just bumping this thread in case denis0625 was wondering where it went. It was one of the ones heavily affected by the database issues that have plagued the forum for the last several days, having disappeared twice and reappeared, finally, again. Hopefully it will remain so he can made his determination, if in fact it isn't too late to help him.

 

[e-420]

These are very similar symptoms on my 420 when the voltage regulator went "north" (up in voltage as opposed to "south", down in voltage". I had done a done a system check at a local MB chapter "garage day" and it indicated a out of range VR. However, no other symptoms so I didn't do anything. A few months later strange things would happen. Everything worked fine with the engine off, or idling with the AC on. then things like the windows, mirrors, seats would function erratically when driving. Voltage was in the high 14's. replaced the VR and problem immediately went away, voltage went to about 13.6 and been perfect for the last 3 years.

 

[denis0625]

These are very similar symptoms on my 420 when the voltage regulator went "north" (up in voltage as opposed to "south", down in voltage". I had done a done a system check at a local MB chapter "garage day" and it indicated a out of range VR. However, no other symptoms so I didn't do anything. A few months later strange things would happen. Everything worked fine with the engine off, or idling with the AC on. then things like the windows, mirrors, seats would function erratically when driving. Voltage was in the high 14's. replaced the VR and problem immediately went away, voltage went to about 13.6 and been perfect for the last 3 years.

Hey, that sounds very much like my car. Did your SRS, ETS and traction control lights pop on as well?

 

[e-420]

Hey, that sounds very much like my car. Did your SRS, ETS and traction control lights pop on as well?

srs no, traction control yes, don't have ets. all kinds of wierd and strange things would go on and very erratic. But everything worked fine with the engine off since the voltage was "normal". I have an idea that the electronics and CANBUS either by design or hapenstance, shut stuff off if battery voltage gets to high, just like it shuts of everything when the battery voltage drops below 10.5 to avoid completely discharging the battery.