Greetings to everyone. I just found this board and think it's just great. I'm having a bit of trouble with my recently aquired 1990 240DL. I got her at 105,000 and did some usual things to tune her up - New Cap, Rotor, Plugs, Air Filter, Fuel Filter, Coolant Flush - changed the OD relay (it was blown). I drove her to 118,500 and then the problems started. I lent her to a friend who broke down and approved a starter replacement at a garage costing me $500. Here in NYC they really rip you off. Anyway, I drove her for about 20 or 30 miles after that, then went on a 200 mile trip. Halfway along the alternator light and a few other came on briefly, then went away as I accelerated. Then I lost all power and had to get towed. I was not in a mood to get ripped off, so I had the tow truck driver take me to an Autozone whereupon I set about to change the alternator in the freezing cold and dark night. I've never done this before, being new to cars, so I gave the driver a few bucks to show me what I needed to do. I removed the alternator -- compared it with the new one (remember, at this point I just spent an hour and a half nearly freezing so my brain is not working 100%) and set about to install the new one. After I put it in I realized that the electrical connectors were slightly different. I have coming out of the wiring harness one thick red wire and one thin red wire. The old alternator had a screw type mount onto which the thick red wire was attached. The thin red wire has a slide on type connector and was attached to the old alternator via a slide on connector. THe old alternator also had a screw mount for the ground wire. Ok, so, the new alternator also had two screw mounts and a slide on connector. But they were in a different configuration. No problem I thought. Just attach the wies where they fit. I Slid on the red wire, screwed on the thich red wire and screwed on the gound wire. Got a boost and jump from the tow truck and off I went, for about 15 miles. Then I lost all power again. I let the car and went back the next day with two new batteries (thinking the old one was burnt out from the bad alternator.) As I drove like a bat out of hell towards home - the alternator lights stay on and eventually the first battery died - put in a new battery - and that got me home. At home I removed the alternator to it to a NAPA - where it tested fine. He checked the computer to see if it was the wrong type of alternator for my car and it wasn't. His computer told him he had one in stock and it looked exactly like the one Autozone gave me. So I brought it home and tried several different ways of wiring it up but none worked so I brought it to a garage. The next day I got a call from the mechanic who told me I had wired it up incorrectly and that when he wired it up right the alternator was not producing juice. He wanted $344 for a rebuilt alternator (sounds like he shops for parts at the same place where as the guy who charged $500 for the starter) Anaway, I thought this was a bit excessive, so I took the car home, removed the alternator and had it tested again - but this time it tested bad. Now I look at the way he wired it up and there is no way I could have known how to wire this alternator up.

Now my question is: IS this the correct way to attach the three wires to the alternator? He attached the big red wire to a post marked "B+" The blue ground he attached via a bolt he inserted into a threaded hole in the alternator (the old alternator had a post just for te ground - this threw me off) and the thin red wire with the slide on connector - he used a modifier - a metal spade with a hole through it to connect it to to the screw post marked "D+" - Why then is there a spade post marked only "+" what is this for? The mechanic said this was some type of plug for a radio suppressor. Is this right? How should I attach the wires? And if I did blow the alternator by wiring it up wrong - could I have damaged anything else that I should keep my eyes open for when I install yet another alternator ( the new one was under warranty) Thank you.