victory3201

I have a 99 e320 wagon that has developed a strange electrical problem. I need help!!! It doesn't matter if the car is cold or warm it started out occasionally and has gotten much worse. The engine will stall and the dash, HVAC, and radio will shut off and on rapidly, while a rapid clicking noise can he heard coming from the dash. I would pull over, shut the key off all the way, and restart the car with no problem. As its gotten worse when you turn the key all the way over before the starting position all the warning lights will flash, all electrical items will flash off and on and the clicking sound can be heard. Turn the key back off and try again, and it will start. Sometimes once started if you push the brake it will cause the same symptoms. I fiddled around with wires under the dash coming from the ignition, and noticed a thick grey wire that had seemed to be pinched slightly, and I haven't had the problem since. However I have not driven it and only let it idle. It is not throwing any codes. What could be causing this?

kajtek1

Sounds like power supply problem.
I would clean battery connections just in case and drive the car with voltage on climatronic display.
This way you can see if/when the voltage drops.
How old are alternator brushes?

victory3201

I will clean the battery posts. As far as the alternator I believe it's original. I bought the car with 135k a couple years ago and it now has 147k. Thank you for your help. How do you make the climatronic show the voltage?

victory3201

I figured out how to put the climatronic in diagnostic mode. At idle the colts are 13.1 while driving the vary between 12 and 13.1. It was the same whether or not the head lights were on or off. It also hasn't had the issue again. Setting 23 is supposed to be for the battery. It only reads 32. Does this mean the battery is low?

kajtek1

I think 23 is battery charge %, but double check it.
Now voltage oscillating down to 12 is not good. Climatronic usually shows 0.5v less than terminals FYI.
It could change +- 0.2 V but you have something going there.
Battery usually is the first suspect, but the brushes wear might be the issue as well.
Do another test at idle with headlights, rear defroster and blower on high and another one with engine at about 2000 rpm.
Take the battery to Autozone for testing as well.

Nashville

honestly it sounds like a relay to me.

victory3201

I took the battery in and it was bad, so I replaced it with the recommended EXIDE. Now the volts are showing 13.5 to 13.1 depending on what I have running in the car. (I do have an aftermarket stereo, and small 50 watt amp powering the speakers.) I drove it all over yesterday with out an issue until I was almost home. The same issue occurred but the car didn't fully stall. It also displayed ASR...something across the screen but only for an instant so I didn't get to see it all. This morning when I put the key in and turned it to position 2 it had the same behavior as before the new battery. I pushed on the key and it stopped. That could have been a coincidence. It started up just fine after that and the volts are still holding at 13.5. Thank you all for your help. Any more ideas?

kajtek1

You are not reporting back how is the voltage holding during those incidents?
Short brushes will act for some time till they completely die.
If the old battery was starting the car, chances are that it was just undercharged.

victory3201

I'm sorry about that! The climatronic reads 13.5 to 13.3 back and forth while I am driving. This has been with the climate control system on, and the headlights. I was able to get it to dip to 12.9 with EVERYTHING running at an idle. When I pressed the accelerator it did not go up.

kajtek1

12.9V on high idle is battery draw.
Your alternator is not giving enough power.
With latest info it also could be bad diode.
You can take it to electric shop for full testing, but IMHO you have 90% chance you need new alternator

victory3201

Thank you so much for your help. Can advance test the alternator? If it is the alternator, where do your recommend I get one? I can replace it myself, I just don't want to get hosed on the cost.

kajtek1

I think advance will test the alternator if you bring it to them, but removing alternator on 320 engine is hard job.
Electric shop can load-test the alternator in the car.
I recall members on benzworld posting source of $200 alternators, so check there.

victory3201

Thanks again. I will check with a local shop on load testing the alternator. Might not be able to get it anywhere till Monday. Another thread I was reading indicated it may be the voltage regulator instead of the alternator. Do you think this is possible or should I just wait and see with the alternator load test?

kajtek1

Not seeing live-data I can only guess, but bad VR would jump the voltage 13.5 down to 12.9 (battery voltage) or less is sharp burst.
If the voltage falls down under the load in linear way, that would be bad diodes.

victory3201

It does change in sharp bursts. It goes between 13.5 and 13.3 constantly. It does not stay on one or the other. With every accessory running it reads 12.9 to 13.1 constantly changing back and forth. After sitting for an hour the battery volts are reading 11.5 with the engine off. After running for maybe 10 minutes and then shutting the car off again and checking the battery volts with the engine off, it is reading 12.5. I hope this data helps!

kajtek1

Such symptoms will be similar for different failures like:
- shortening battery, (what you eliminated buying new)
-worn out alternator brushes
-bad diodes that give some charge, but fail under load.
-could also be some current draw
The difference that would allow experienced mechanic to pinpoint one over the other possibilities are so subtle, that I can not make it from the description.
11.5V battery will not start the engine, so it has to be error?
One more thing you can do is measure car current draw with engine off and ignition on and then off. Put ammeter between battery post and cable.