83 300D electrical issue

[MBDFahrer]

Good Evening,

On my drive home this evening from my friend's house, the W123 i'm driving is giving me electrical issues. The tach, fuel and coolant temp gauges all don't work, turn signals don't activate and when turning the car off, the battery light came on. Do all signs point to a alternator on its way out?

And all this happened because I got the new injector line for my W124... I assume?

[Brian Carlton]

Well, the alternator could be the issue, however, the complete lack of gauges and turn signals could be as simple as a bad fuse.

I had the same symptoms, intermittant, on the 123 when I owned it. The gauges and turn signals seemed to decide not to work in very warm weather. When I finally realized that I should change the fuse, the aluminum portion was found to be cracked in the center.

Change that fuse first. Use the brass or copper replacements. Then see if you still have the issue.

Check the battery voltage with the engine running at 2000 rpm. It should read at least 13.5 volts. If it reads 12V, or less, you definitely have an alternator problem.

[phantoms]

Could also have been the key not exactly in the run position. If all is well tomorrow, then it's a good bet that was it.

[MBDFahrer]

Originally Posted by phantoms

Could also have been the key not exactly in the run position. If all is well tomorrow, then it's a good bet that was it.

I don't think so...?
Tried jiggling the key, when I got home, turned off the car and back on, gauges still didn't work and the battery light stayed on until i gave it a little press on the go pedal.

Batt light coming between the time when you switch the key off and the engine stops turning is normal.

I just replaced the regulator/brushes on my 300SD and I couldn't be happier. You have to be careful though becuase the thing inside the alternator that the brushes rub agaist (slip rings) are known for getting deep grooves in them and actually failing electrically. If you feel a small ridge in there when you have the regulator off, then you are ok. Its hard to judge (or tell) what is too deep...I used to rebuild these all the time and we always replaced the slip rings.

But we didn't have them still in the cars either

[mgt83300D]

Replace all the aluminum tipped fuses with copper tipped ones. These will produce all kinds of intermittent electrical problems. This fixed mine.

[MBDFahrer]

It surely was a aluminum fuse, took it out and put it back in, and it went away, replaced 2 glow plugs today too and starts much easier.

The battery light still comes on at night. Checked it with a voltmeter and the engine running and its ~13.5 volts.

Guess its just a cold thing?

[Brian Carlton]

.......when a plan comes together.

With regard to the alternator light on at night, please explain if the light is on bright or whether it is "ghosting". Ghosting is when you can see a dull glow from the light. You would not be able to see this in daylight.

[mgt83300D]

Here's a nice kit that I'd recommend installing. This company really does a great job of helping owners maintain our cars.
http://www.**************.com/
purchase Item # COMEKU-FKU Fuse Upgrade Kit

[MBDFahrer]

Originally Posted by Brian Carlton

.......when a plan comes together.

With regard to the alternator light on at night, please explain if the light is on bright or whether it is "ghosting". Ghosting is when you can see a dull glow from the light. You would not be able to see this in daylight.

Full bright light, but with a dab of throttle, it fades away

[Brian Carlton]

Hmmmmm.........I'm guessing here but it appears to be some type of issue with the diode circuitry to the light. The light appears to be responding to the alternator at idle when it puts out little current. Above idle, the alternator has a decent output and the light goes out.