1995 E320 Wagon serious electrical issues
 

Yesterday as I was driving home my car starting acting completely wrong.

The order of events were as follows.

First, the radio turned off and the ASR, ABS, SRS, and Check Engine lights came on.

Then the vehicle shuddered as a started to pull over. Then the engine quit just as i was pulling into a parking lot.

I tried to start the engine after that but there was just a clicking under the hood, (not the starter motor) and the windshield wiper decided to operate slowly. Then after that nothing.

I called a friend and he deduced that it was a internal short in the battery. Which made sense at the time. He came with a new battery and the care worked fine for the 40 or so miles home.

Now today, I was driving home from class, Im getting to a stoplight and the car shuddered and all the same idiot lights came on. Immediately I turned off all powered devices. Radio, aircon and fan, and unplugged my charging cell phone. That seemed to buy me time as the idiot lights turned off. I made it the 5 miles home but only just as the car died in the drive way.

It has the same post incident symptoms as yesterday. Clicking and wiper operation.

Now I have no idea where to go. I suspect the alternator but the battery warning idiot light never illuminated so Im hesitant to replace a good alternator if I don't have to.

Let me know what you think.

Thanks in advance,

Gregory

sounds like your alternator isnt working and you have drained 2 batteries.....could be volt reg, I'm not familiar with your car though

Definately the alternator, the idiot light on that car is not a reliable indicator.

alternator all the way

OVP relay
 

A very knowledgeable tech told me whenever a 124 comes in with problems, the first thing he does is replace the OVP relay. it is located aft of the battery, takes 10 minutes to replace, and costs $100. It affects a large number of devices and circuits.

This is a good thing to consider. Much easier than replacing the alternator.

To add to the story a bit. I broke our the multi-meter and tested the battery leads with the engine running. The Voltage is dropping even while revving the engine.

I would question to a certain extent a knowledgeable tech who immediately replaces a $100 part when a car comes in "with problems". Not trying to be snarky but yeeesh people.

Anyways, what I would do first is yank out the voltage regulator to look for worn out brushes. At that point, if one or both are worn down, you would probably be better served replacing the regulator. Other course of action is to get the battery charged up and take it someplace to get the charging system checked. This is what the next step would be if the brushes look good. back when I was a tech the first step was to check the charging system and if it was low output (less than 13.8 or so) check the brushes. A poor mans way of testing would be to check batt voltage with the engine running, again it should be 13.8 to 14.4v when running. To be fair make sure the major electrical consumers are off, AC and blower fan, headlights, etc. The charging system or battery makes way more sense than a the OVP given the symptoms.

Well using this reasoning, fine, replace the oil cap first but it won't fix the problem.

Its the alternator. All the lights on is red flag alternator down....the new battery drained completely is just the icing on the cake.
New Bosch alternator and be done with it.

PLEASE do the correct procedure for loosening the belt tensioner otherwise expect a new one either immediately on the near future.
OVP relay fixes a lot of issues, however, this is not one of them.

Okay, order has been placed for a new voltage regulator. Hopefully that is the problem and not the alternator.

Will update when i know more.

Alternator/voltage regulator 100%

Your sig show 200K on subject car.

If the alternator is still original, you are past the window for replacing it.
Alternators generally last between 160-180K miles before needing replacement.

Replacing the VR on an original alternator with 200K miles is not a lasting solution.

The dash light that should glow when the alternator is not putting out sufficient voltage is in series with the exicitation voltage. Unlike a generator, an alternator needs a voltage source to begin charging. As voltage reaches parity between battery and alternator output the light doesn't light, as there is the same DC voltage on either side (i.e., no ground). The alternator/regulator CAN fail in a manner that will not light up this light, it's happened twice in my cars.

Jim

I have never had one light up the dash light when it failed, and I have replaced 5 alternators on several cars.

all the warning lights coming on is an indication that the alternator output is lower than battery voltage. - its the self check system coming back up (just like when starting the car)

the SRS light will also light up with lack of voltage.

Jim, although we don't know if it's the original alternator or not, so what I would have done is pull the VR and check the condition of the (loss of tech term here) the rings the brushes press against. Can sort of tell by how deep the grooves are that are made by the brushes.