Help: no horn, no turn signals, no winshield wipers
 

Hi all --

I did a search but did not find a conclusive answer to my problem.

The Symptoms
Just today in my 1999 W202 (C43), my turn signals (left and right) did not come on when I moved the stalk to indicate a turn. At the same time, neither the winshield wipers nor the winshield washer fluid came on when I turned or pushed the control stalk. I also tried the horn and it did not work. Strangely, when I pulled the light switch out to turn on the fog lights, neither they nor the led in the center of the light switch came on. However, the highbeams and the blue indicator light on the gauge panel did work.

About 30 minutes later the turn signals and winshield washers started working normally again, I didn't try the horn, and the fog lights came on but the led in the center of the light switch did not come on.

What could be the problem? I truely need help with this one.

Previous posts here and a Club202.com indicated that this problem may be caused by a faulty voltage regulator (on back of alternator), a bad wiring harness or a bad master relay. None of those posts gave the final solution to or the exact cause of the problem.

Any help would be appreciated.

Thanks,

That's a tough one. What is the status right now? Is everything working, or just the foglight indicator is inop or????
My gut reaction would be the ignition switch (EIS). There may be fault codes stored to look at. The EIS would require a shop to do it that has SDS, and possibly only a dealer.

Gilly

wiring
 

Would follow-up whatever Gilly suggests, he's the pro. However, by the way, a "bad wiring harness" can sometimes just mean a bad ground. Sometimes it's simply a matter of regrounding that part of the wiring system (for example, a grounding point somewhere that's gone bad and regrounding the questionable components to another new ground).

I'd also check the fuses for the indicators going bad (turn signal, etc) to see if one is going bad and cutting-power intermittently.

Ditto on the fuses. Twist the fuse in its socket to break any corrosion causing intermittent contact.

I am having a problem with the delay on my wipers (I have already replaced the motor). It has been suggested that the problem is the combination relay. When this was mentioned the comment was made that the problem usually effects other items at the same time (like the blinkers and other items on the steering column). If you can find someone else with the same model car you may want to check this out as an option (make sure you verify the part # also).

Good luck!

Tump,
Was the engine area WASHED or cleaned just before the problem started?
They can get wet when washing the engine as fuse box ISN'T sealed that well.

That car has a signal activation module (SAM) that controls all of those functions, codes may be present in that module.

Hi All --

Thanks a lot for the help! So far the none of the symptoms have returned, even the fog light switch works properly. My earlier post may have been incorrect about the led on the fog light switch. That led is only supposed to come on when the switch is pulled out to the second stop (indicating that the rear fog lights are on) and it works fine now. I do not remember if I pulled it out to the second stop when the symptoms first appeared.

I have an appointment at the Stealership on Nov. 11, (warranty expires this January) and I will mention all the possibilities you listed.

The engine has never been washed and, to my knowledge, has never encountered more than a couple of rain drops.

I will check the fuses and I may check the voltage regulator before I bring the car in. But I will be certain to have the Stealer check the ignition switch (EIS), the combination/master relay, the signal activation module (SAM) and the wiring harness paying particular attention to the various grounds.

Thanks to M.B.Doc, Cal Ratcliff, Kestas, dreamer, ericgr, and Gilly.

same problem here
1993 300SL
I was trying to trace some electrical wires
next thing I know no signal light, no winshield wiper, no horn
I must have shorten something.
let me know please what is your outcome

thanks

Well, I took the car into the dealer's for warranty repair and described my problem exactly as I did above. I even suggested that they analyze all the items listed above by our experts, including the voltage regulator. All they said was "No defect found at this time." I didn't get to speak to the technician so I do not know exactly what he looked at, if anything, besides the vehicle's error codes.

I did, however, get them to replace both fuel level senders and my inoperable infra red key under warranty so, I can't complain too much. So far I've also had them rebuild my othopedic driver's seat; replace my automatic climate control unit; replace my compressor w/ clutch, condenser, temp sensor and a/c drier;replace my radiator, steering damper, outside temp sensor and fuel shut off sensor; remap my transimission; and replace the driver's side view mirror motor all under warranty. I believe that this is worth more than the $1,700 I paid them to extend my Starmark.

My original electrical complaint is documented as having occured prior to the expiration of my starmark warranty so, I hope that should this electrical problem surface again they will take care of it under warranty or goodwill.

Thanks again for your help,