My Friday the 13th W124 Electrical/Stalling Woes - PeachParts Mercedes-Benz Forum

Addbhp · #1 02-16-2009, 07:56 AM

On Friday, I left work no problem, and got about 20 kms, when the ABS light came on, and then followed by the SRS light. Never having seen the SRS light before, I pull over, turn the car off to check the manual and fuses. Not seeing any fuses out, I go to start the car, and get nothing. Oh oh. After about 5 minutes, the car starts again, which is good news, since I'm miles from anywhere.

In the past when the ABS light has come one, it's only ever been for a few seconds or a few minutes.

I get about 10 minutes further along, when the lights reappear, and the car stalls, and I'm able to coast to the shoulder from the highway. Patiently I wait again for about 10 minutes, and the car starts again. Worried about the fading day light and traffic, don't feel good about the situation. Driving with no radio,heat, rear defrost and only daytime running lights, to put less drain on the electrical system, I am correct in worrying, as I only get about 3 minutes along the highway and lights reappear for the 3rd time and barely get to the shoulder yet again.

Having read about the OVP relay in the past, I figure this is the culprit, so don't want to pay huge dollars for anything else. Unfortunately traffic is insane, so figure there is no point even trying to start the car again, until traffic clears, and I get get from the express lanes to the collectors and off at the next ramp, about 2 kms away. Patiently waiting for traffic to clear, after about 20 minutes a tow truck appears, and I agree to be towed off the highway to a mall parking lot about 3 kms away. After getting something to eat and waiting for my wife to pick me up, I am able to start the car again, no problem and move it closer to the mall.

Thinking it's just a OVP relay, I leave the car their until Saturday when I can get the relay and drive home.

Saturday: After installing the part, I try to start the car, and it would appear the battery is dead. After a boost, I have my wife follow me home. Ah not so lucky, again after about 15 minutes, of driving the ABS and SRS lights reappear, and again at dusk, I am losing electrical, lights diming, no heat, ugh. Make it to a gas station along the highway, the 300e is dead again. After a boost, the car starts, but before even getting anywhere, all lights reappear, and she dies.

Before I incure huge repair bills, where do I start, I imagine the battery is dead now, and is this an alternator probem. I have tried to be as detailed as possible in the hopes that someone can help here.
Thanks, Sorry about the long post.

pawoSD · #2 02-16-2009, 08:03 AM

It does sound like a low-voltage/power condition. But I bet its just a worn out voltage regulator....might be able to get away with just replacing that ($30) instead of the whole alternator....

Uncle Acky · #3 02-16-2009, 11:18 AM

agree with above post. My 92 300e had same problem due to bad V regulator.

In my case, I checked battery voltage (after charging) 12v and then started the engine re-checking battery voltage which should now be 13.5 to 14 engine running.

In my case with engine running battery v stayed at 12. I gently tapped the voltage regulator (at rear bottom of alternator) and the engine idle changed slightly, this also produced a slight whining noise from the alternator.

Now batt v was at 14v. and I was able to continue to drive the vehicle until I replaced the regulator. I connected a multimeter to the cigarette lighter to keep an eye on the charging system. I only had to tap the regulator (occasionally) one time after start up.

On the off chance that yours is a similar problem, this may help.
good luck ,
Acky

Addbhp · #4 02-16-2009, 05:16 PM

Thanks for the responses.

Is this Voltage regulator something I can replace easily on my own, or does a shop need to do this? I don't find a lot of space near the alternator.

Do you think the battery will be pooched?

J.HIDALGO · #5 02-16-2009, 05:49 PM

in a 300e. Why type of 124 do you have?

Addbhp · #6 02-16-2009, 08:44 PM

90 300e, so 5 minutes, that's encouraging. Where exactly does it go? Any pictures? Based on what I indicated, do you think the battery needs replacement, or after it's boosted and running it should be okay?

Uncle Acky · #7 02-17-2009, 09:25 AM

Here is a pic of the regulator

I hope that worked......

http://www.thebenzbin.com/includes/secure/popup.php?type=more&image=aHR0cDovL3d3dy50aGViZW56YmluLmNvbS9wYXJ0cy9pbWFnZXMvcHJvZGltYWdlL2ltYWdlcy9XT1JMRFBBQy9XMDEzMz E2MzQ5NjBLQUUuSlBH&title=S2FlaGxlciBWb2x0YWdlIFJlZ3VsYXRvcg==&text=PGI+PC9iPg==

About your battery, my crystal ball says you should charge it fully and then have it properly tested with the correct tester...this should be free at CTC or Partsource etc.

dpkreuze · #8 02-17-2009, 12:16 PM

Friend,
When you insert the new regulator exercise caution. The carbon contact brushes are spring loaded. Try inserting the regulator at such an angle as to compress the brushes onto the slip ring in the alternator first. Hold the unit tightly against the alternator housing as you insert the fasteners. So you may want to have a fastener in your hand when mounting up the regulator. "You can do eet"
Peace

Hirnbeiss · #9 02-17-2009, 01:00 PM

disconnect battery to avoid unplanned death

pawoSD · #10 02-17-2009, 02:12 PM

Quote:

Originally Posted by Hirnbeiss

disconnect battery to avoid unplanned death

I don't know about death from 12Volts....maybe some pain though...

Hirnbeiss · #11 02-17-2009, 07:53 PM

Quote:

Originally Posted by pawoSD

I don't know about death from 12Volts....maybe some pain though...

Survivorship effect: the dead aren't there to tell their tales

pawoSD · #12 02-17-2009, 09:34 PM

Computers are more dangerous than cars electrically....just tonight I replaced a fan in my dad's PC's power supply....inches from capacitors with over 10,000 volts in them.

That, is dangerous!

Addbhp · #13 02-18-2009, 02:13 PM

Unfortunately ended up having to tow the car to a garage to finish, as when I tried to remove the regulator, the screw heads were starting to strip...phillips heads are near useless. Can't believe I need a garage to remove two screws for me....didn't feel like laying in the snow in a parking lot today to try and get these out.

Hirnbeiss · #14 02-18-2009, 02:28 PM

Consider a hammer impact driver for future battles with stubborn cheesehead screws. Saved me on many a motorcycle crankcase cover.

Addbhp · #15 02-19-2009, 11:09 AM

Problem solved, new Voltage regulator solved it all. Having seen the old part, wow compared to the old bushings they had about 1/4 of the material left vs. the new one. Thanks for all the response and help.