BenzWorld Junior Member
Date registered: Sep 2012
Vehicle: 1977 240D
Mentioned: 0 Post(s)
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'77 240D W123 warning lamps out and not charging.
My 77 240D (W123) is currently not charging, and none of the warning lights turn on for lamp test when I turn the key to any position. The glow plug light comes on, fyi. I know the warning lights were working not long ago but can't say when they stopped. I've been working on the car and this may complicate the diagnosis. I put a new battery in a few weeks ago because I knew it was old and as the temperature was dropping, it was cranking slower. Warning lights were still working at that time. A few days after replacing the battery, i replaced the voltage regulator, as I'd pulled it about a month previously and knew that the brushes were fairly worn down so I ordered a replacement.
I'm not sure if after replacing the regulator the warning lights still worked or not. I started the car but didn't check the alternator output. (crap!)
About 3 days later, (driving daily) I blew the cigar lighter fuse when my GPS charger cord shorted. I replaced the fuse but still didn't notice whether or not the warning lights were working or not. I drove the car the next day, but on the second morning following the blown fuse, the car cranked over very slowly and wouldn't start. I checked the voltage, after boosting the car and found the battery voltage was 11.91 and no increase with rpms.
I did some forum checking and found that the charging lamp was required to excite the alternator field so I replaced that, but still no charging voltage.
So, I currently have no charging from the alternator and the brake warning/charging lights fail to come in in self test, and the charging light doesn't come on either. Fuses are all good. Alternator belt is tight.
Any idea as to what may be wrong, or what i should check next?