hey guys i have been trying to help a friend install an alternator on his 1988 240dl and there have been some complications. To start with im just doing him a favor and helping him but this is the first volvo i have ever worked on. So he came to me asking for help in installing the alternator. The first time we attempted he had bought the generic one from advanced auto we installed it conected the fatter red wire to the biggest post and the blue wire to the smaller post right next to it ( i later learned this is the wrong wiring the was also a smaller red wire with a spade connecetion that we tapped off). I quickly figured out this is not how it was supposed to be wired so i removed it connected the blue wire to the groud post at the bottom of the alternator the thin red wire i put a circular connection on and put it on the d+ smaller post and the fatter red wire to the B+ fatter post. i installed it and turned the car on i checked the battery and the multimeter was read 10 with the car off and almost 12 with the car on so i determined that battery was charging but was kind of skeptical. so we start driving the car and he said he heard a Horrible noise i popped the hood and say the one of the serpintine belt pully( or whatever you wanna call it) was slightly hitting that little square metle piece that hold the alternator on and tensions the belt ( i guess that what it does). so we go to try and repostion it out in the street and a wrench fell and caused a spark on the alternator. worried that we fired the diodes i checked the alternator and sure enough it wasnt working... so we decided to go buy the bosch one becasue he wanted that one anyway and put it in last night and now its still not working does anyone have any advice on what to do next is there a fuse for the alternator? could something else be damged from the spark? sorry for this being so long any help would be great? also there is a little black wire that goes back into the motor looks like some kind of sensor what does that do and that black wires clip broke and became disconnected.
(that black wire)

 

bump still need help on this???

 

Your post is just a little hard to follow, that may be why no one has offered solutions yet. From what i understand you had difficulty reinstalling an alternator after u took it off to tighten a belt? and you noticed the the belt tensioner was hitting the belt? then u dropped a wrench on the back of the alternator and you believe that killed it. bought a new bosh one and still cant seem to get it to work?

My Advice, Re-check all your fuses, and the wiring to the alternator. The fat red wire in the picture is your current to the alt, the black/blue wire should be ground, and the little red one should be to the alternator "light" in your dash from what i understand that light being burned out can cause some issues. not saying thats what you have, just might be something to check.

Also there is a bolt you have to loosen before you adjust the tension on the belts in these cars, (unless were talking the timing belt) be sure to loosen the short fat bolt first or you will bend your tensioner and tensioning bolt. Thankfully they are readily available. I bent my alternator bolt the first time i adjusted it...

maybe we can get one of the experts to chime in..

best,
BBman

 

indeed, the skinny red wire from the D+ terminal to the dashboard alternator light is a critical part ofthe circuit. if that light is burned out (or the wire isn't connected correctly), the alternator won't jumpstart itself, and won't charge at all. the other side of that alternator light is connected to the ignition switch so it gets power when the car is switched on, this provides a 'tickle' voltage to the alternator, which it uses to start making real voltage.