Help with an electrical hiccup, please.
 

Every now and then, while idling, the electrics in my C240 seem to hiccup. By that I mean, the lights go out, the engine dies, everything goes off for a very brief half second. Its not long enough to actually stall the engine or to default the electrics, but it is very wierd when it happens.

Is this something I should be worried about? I'll be going in for a scheduled maintenance in another 900 miles or so, and I thought I'd ask them to look at it. Of course, if history is any indicator, they won't have a clue. (I don't have time or room enough here to go into all the diagnostic problems I've had. It's almost like they've never seen a Mercedes before!)

So, if anyone has any ideas, I'd appreciate your thoughts. I've found it useful to go in with some ideas of where the problem may be--sort of give them a running diagnostic start.

Thanks in advance.

Eric

You didn't mention what year your car is, but I would reasonably guess that your voltage regulator is starting to go out on you. I'm not sure but on newer MBs, it's internally mounted in your alternator...translation, you don't get to replace the regulator, but the more-expensive alternator it's embedded in! :(

I'm not sure if the problem will show up in a charging system test. Failure is abrupt in many cases. I've had vehicles that had a clean bill of health with the electrical test...only to have the charging system fail days later! :mad:

But as a backup measure, check your fuse compartment for bad fuses, and inspect the engine area for any loose connections...

Thanks for your reply....
 

I did, indeed neglect to mention the car details: C240, 2002, 9000 miles.

Thanks again for your suggestions.

Eric

All of the aforementioned tips just went out the window given the year and mileage of your vehicle...I had anticipated a fully broken-in vehicle with probably ten times the mileage of yours.

I would check the battery connections to make sure they are tight. I had once purchased an SUV right off the showroom floor, but the dealership never bothered to tighten the battery clamp down before releasing the vehicle. So, during its maiden voyage, all sorts of intermittent problems came up, lights went on in the dash, etc., before I had discovered the ground lead just resting (not seated) on the terminal!

Have the dealer check all electrical fittings, specifically where major wiring harnesses are connected. Have the charging system checked anyway as a precaution.

You might also check around for other MB specialists in your area if you aren't satisfied with your current service facility. Most authorized repair shops will honor the factory warranties. Post a thread in the "Good MB Shops" forum.

Some thoughts...
 

Hi Ducatista,
Based on your original post, here are some thoughts for you to mull over, and questions to clarify the issue. First, you said "while idling". Does this mean that it only occurs while idling? If so, it means that the alternator is most likely hiding the problem when the engine is running at a high enough rpm for the alternator output to supply adequate current to replace the battery voltage/current. This is significant, as it means that there most likely is an intermittent open somewhere in the supply from the battery to the engine circuits, including the alternator. You said that "the lights go out" - I'm assuming that the only lights you are referring to is the dash indicators. Is this correct? If the headlights and running lights also go out, the problem can only be the battery or associated connections, as the alternator output goes quite directly to the battery lead. If only the engine indicator lights go out, it could be a problem with the supply from the source (Fuse box or circuit breaker) to the engine harness.
Incidently, don't forget the battery ground cable as a possiblilty. Also, don't forget the grounding strap from the engine to the frame as a possibility.
Good luck with the problem, your vehicle is still almost new, MB should assume complete responsibility for this one!

Richard Wooldridge
'82 300D/4.3L V6
'94 Taurus
'88 Astrovan
'85 GMC S15
'77 Jag XJ6
'77 280Z
Etc....

Given the year and the mileage of your vehicle, I wouldn't even bother to post it (I mean no offense).
Go straight to the dealer.

Given the year and the mileage of your vehicle, I wouldn't even bother to post it (I mean no offense).
Go straight to the dealer.

Hey, thanks to all...
 

I appreciate your assistance. As I said originally, I am taking this to the dealer, but they are so inept that I want to give them some direction. I've had success with this approach in the past.

Had a stumble on acceleration between 3500 and 4500. Posted it, and got a list of three or four real possible causes. Took it to the dealer (with the list). They said nothing was wrong. I said keep it until you figure it out, and by the way you might want to go through the list of possibilities I left previously. Two days later, the shop forman asks me where I got the list, as the problem was indeed one of the items (replaced the fuel module--not an uncommon problem among late-model C-class 240's).

Considering the clientele to whom this dealership (and most Mercedes dealerships, I assume) is catering, I can't believe how crude their shop and service departments are. I had better service from my Saturn dealer!

Thanks again for all of your suggestions. Forewarned is fore-armed!

Hiccup Update
 

R&H Mercedes in Riesterstown, MD, had my car for a week. Did absolutely nothing to fix the problem, except to tell me that it did not exist! Since they couldn't duplicate the problem, they refused to even look further.

I cannot recommend R&H for anything. They do not return calls (I had to call four times over the course of two weeks to even get my "advisor" to call me back to make the initial appointment!). They are unable to repair even the most rudimentary problems.

This is the second time I've had dismal service from them. Took the car up to Hunt Valley Mercedes. Gave them all of my info to "change dealers." Maybe they can do better.

When I upgrade to the C32 in two years, I definitely will not be shopping at R&H.

Eric