where attach alt ground??

[dom0988]

I bought my 240 with a newly rebuilt motor. I've been having the ebrake and battery lights problem so i had my battery and alt checked and everything was fine. I came across something that said to check your alternator ground. Turns out the guy I bought the car from did not ground the alternator, so I think thats the at least one problem. My question is where on the alternator do I attach the ground wire? Can't find it in my FSM. A picture would be very helpful. Sorry for the newb question, but I have searched. O yea it's a 1990.Thanks

[jdm_master_X]

i believe it to be the 8mm bolt that is attached to the alternator. there should be one black ground wire with a terminal for you to attach it to the alternator.

[dom0988]

thanks for your quick response. I'm not sure I really know what you are talking about though because A.) I'm a complete newb, and B.) I don't think he attached any ground wires. I could very well be wrong though. I was able to take a crappy picture of it with my video camera though, could you show me what you're talking about? sorry thats the best angle i could get w/ a video camera.Thanks again

[DjPantsSpecR]

there are actually two grounds, and you need both.

one, adn most importantly is the nut closest to the right in that pic. it has a plastic collar, it looks like you've already hooked up that wire.

the second ground is one of those 88mm little guys twords the top of the picture. if i remember, i think it even has slots for a screw driver in it

[dom0988]

Well I didn't do any hooking up of any wires. Since that main ground is already hooked is it safe to assume that it is at least properly grounded? Also the only bolt with a screwdriver slot already has a wire attached to it. I tried to point it out in the pic below. So if both of those are already attached is it just a matter of finding where he left them dangling? You can hardly see it. It's the bolt right under (in the perspective of the pic) the bolt with the plastic collar.

[dom0988]

I also forgot to mention that at high rpms all my lights flicker. Not on and off, but just brighter/dimmer. I'm not sure what exactly that means, but i assume an alternator that is not properly grounded could have that affect on lights?

[DjPantsSpecR]

definately, and it caan affect charging.

i eventually got a full battery drain and the car started ot run like *** and then just died. we jumped it like ten times to get it home a mile and a half.

what looked like a bat alt, was jsut that that small ground had come loose and was no longer attached. i'm sure other things came into account as well, but it definately does make a difference

[12Ounce]

Yes, if that scew is slotted ... it is probably intended for the ground wire. Not all alternators use a slotted screw, but they are usually all very small diameter and do nothing but allow a case ground connection.

BTW, I do not see the ground wire in the photo... is it up inside the harness cover somewhere?

The large cable that is attached to the insulated post is not "ground" (or zero volts) ... but it is the main 12 volt positive output. Some call this the "hot" terminal.

Have you measured the output voltage? AutoZone can do it for you with alternator still mounted to engine. Output should be 14 volt+.

[dom0988]

/

BTW, I do not see the ground wire in the photo... is it up inside the harness cover somewhere?

So then what the heck is that wire bolted down by that slotted screw? I know it's hard to see in the pic, but the wire has a little orange rubber or plastic sleeve then the wire is black and goes into another bundle of wires. I went to the Nissan dealership today and ordered what should be the wire to ground the alternator. Is the alternator ground going to be a steel braided strap like some other grounds are? If that is the case then should i just disconnect whatever is already on the slotted screw and attach the strap I get from the dealership? Thanks again everyone for your information and advice. O btw I have gotten tested and everything checked out, but i might get that rechecked because I'm a little doubtful of the competency of the guy who did it.

[12Ounce]

OK ... I didn't see the wire under the slotted screw head ... if there is one there, I don't think you have a ground issue.

I rather suspect one, of the three, "phases" of the alternator is out. Perhaps a bad diode, perhaps an open coil .... ??? A good benchtest by AutoZone will prove this sort of thing out.

[dom0988]

I just got back from Advanced Auto Parts and my suspicions were correct. The first guy that tested it did it incorrectly and its the alternator is only putting out 25 amps. So I just bought a new one. It would make sense I think that 25 amps under load would be why my battery light and e-brake lights are on and buzzing (well something is buzzing) as well as at high RPM my lights flicker. Thanks a lot to for everyones advice. Hopefully this new alt. will clear up the problem