i have been having trouble starting my 240d. it will not start unless jumped or on a freshly charged battery. the belt to the alternator looked really bad and it was loose so i removed it and replaced it. while i was down there i removed the alternator as well and had it tested for good measure. two birds with one stone right? so i had tested and it was fine but i noticed something odd about it. it has a pin off to the side, away from the main connection. it is just a bare spade terminal and i cannot find anything in the car that would plug into it. i just bought this car and am trying to get it in good shape so i ask what if anything is this terminal for? i have not done any testing of the car so far as i have just finished the work on it. it did'nt start the first time that i tried to start it but i think that they gave me a shot battery that looks new. because i put it on the charge last night and today it gives voltage just not anymore than enough to make the starter solenoid click. so i will jump it drive it around for twenty minutes or so park it back at home, stop it and try to start it again if it starts then the alternator is fine and the battery is the only problem i have left because it can not hold a charge for more than 24hrs. if there is further difficulty is ther any place that i should look in the car for common parasitic drains on the electrical system. there has been an aftermarket stereo installed so if no one knows i'll start there.

thanks
juan

P.S.
the fuses look funny can anyone tell me where to get replacements and what the color coding is. could i use the glass buss fuses as a replacement for any that blow?

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I would lay odds that the extra terminal on your alternator is for a noise suppression capacitor. If your radio is not picking up alternator "whine" then you don't really need it.

The fuses are old style European fuses and available at just about any car parts place that I have ever seen. However, the copper fusses will be the most trouble free. Those you will probably need to go to FastLane for.

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Sam

84 300SD 350K+ miles ( Blue Belle )

If the battery looks new it may be parasitic drain as you mention. Easy test is to remove a battery cable and let car sit for the twenty four hours. Of course you must make sure battery will crank prior to removing terminal. If it starts you know it is a drain condition. Or you could take your battery to a place that offers free testing.

i put that battery on the charge all night and then left it unconnected for a day. it can not hold a charge. the people that i bought this car from weren't very nice.

the open spade connnector is apparently for a 'stator' connection. I have two alternators for my 240D - one has the connection, one has it connected to a plastic box on the body of the alternator.

My car runs fine without a connection to it.

U need to find out if your alternator is putting out at least 13Volt,
2nd is fully charged yoru batt, get a load test, if batt has less than 500 cranking amps, u can give her to someone else. A diesel u need 600 Crank amps or more, 1000 is not excessive. That tester is a volt meter with giant resistors. Is re-creating the high current draw, see if your battery's voltage drops significantly.

Not point to keep wandering in a Bat cave!

I just had my Alt replaced, the old one was not putting out enuf voltage, and the front bearing is noisy, and squeaky. I was able to quiet her down with some old tranny oil. it olny lasted a day or 2. Finally my bro send me another Alt from his spare engine. Now the voltage goes up before I drove 2 blocks.

Buying a voltage indicator for Walmart etc. Is under $10, very useful , it saved my A** many times, it'll tell me if the Alt is not putting out enuf voltage so u make plans. Rather than died on the side of the road.
The fuel injected gas engine were more un-forgiving, reason they have to run high pressure fuel pump, the faster she goes the more she needs Electricity.

The open spade is for a capacitor

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1977 300D Lost coolant while someone else was driving
1983 300D Can't run without oil
1985 300SD (gone but not forgotten)
1990 300TE 4matic Sold
1991 Yamaha Venture
1975 Kawsaki 250 triple
1974 Honda 200CL
1951 8N Ford
2008 Wildfire 650C

Hehe...thats why we own diesels...

You can start them up and they won't quit unless you shut them down. No electricity required.

Diesels make up for all the juices when starting too.
Either way if your charging/battery is not up to snuff, U're getting screwed thats all.