Hi everyone. Great site you have here.

I have a 1991 Volvo 240, on which I am currently installing a new alternator. I could use a bit of help with the correct way to connect the 3 wires(2 wires, 1 clip-on).

I was over-seas for a couple of years, and my kid brother decided to 'help' me out by doing some needed repairs to my car before I came home. All he actually accomplished was removing several parts from my car and not replacing them, one of which is the alternator.

I'm honestly not much of a mechanic (at all), but I would be able to do this if I had been the one to remove it. Unfortunately, that isn't the case and my brother can no longer recall how it was connected.

So...I am assuming that the fat red wire (battery I think) goes to the larger of the two connections on the alternator, and so the other wire(ground maybe?) goes to the smaller one? I think I have that part correct, but let me know if I do not.

My question is about the 3rd connection, which is in the form of a clip-on attachment and runs along side the fat red wire. Does this clip-on wire go on the same connection as the fat red wire, or the smaller one?

I've googled everything I can think of to find the answer, so any help would be greatly appreciated. I have been trying to get her running for about 4 months (it sat for so long that I have come across multiple expensive problems so far) now and I am at my wits end.

Thanks in advance!

 

Oh, I forgot to add that I somehow managed to get a bit of oil on the clip-on connection. Can anyone tell me if this is a problem or not? I'm a little nervous about hooking it up after I noticed the oil on it. I'm assuming that I can cut the connection off and replace it, if the oil on the connection is a problem.

Thanks so much for any advice you may be able to offer.

 

On the back of the alternator you'll have a large terminal for the battery connection, a small one for the battery light in the instrument cluster (smaller red wire). You will also have a ground wire which connects the case of the alternator to the chassis. A total of three wires.

 

Is the connector you are talking about a spade clip? What color is the wire it is attached to...red? Hook them all up individually. The wires are your main power wire(mine is black and thicker on my 92 245, a ground wire usually blue and a small red wire for battery light on instrument cluster/exciter wire. Main power should go on larger connection, battery light wire smaller on top, the grond can just go on the bottom...just needs to be grounded. Hope this helps...

 

Thanks a lot for the quick reply!

Ok, cool. So I had that part right at least. :P

I believe this is the wire I am unsure of where to connect. I know that it attaches to one of the two terminals, but I do not know if it should be connected to the larger terminal, or the smaller one.

The clip-on connector is small, so I assumed it would go to the smaller terminal...but from what you said about it being for the light in the dash, it makes more sense that it would connect to the larger terminal.

So, yeah, I've no idea which one it goes on.

From what you said, I believe that I have this wire connected properly as well.

The only bit I'm not clear on is which terminal the smaller red wire for the instrument cluster should be connected to.

Thanks again!

 

Yes, a spade clip..and the wire attached to it is small and red. The thick battery wire is also red, and the ground is blue.

Ah, yes, thanks! That clears it up for me perfectly, you are a life saver!

 

I am having similar issues. The used but working alternator is not charging the battery. It is obvious where the thick red wire connects and the thin red wire. The thick black wire is also connected - grounded to the block. But where does the thin black wire connect? When I purchased the car it was jammed inside the oil pressure sensor but has popped out since then.


Does anyone have a sketch showing how these wires should be properly connected. Even a pictured will do. There are four coming out of the harness (2) red, (2) black

 

a standard bosch alternator has ground, B+ heavy red wire to the starter and on to the battery, and a skinny wire from the dashboard alternator light goes to D+

D+ is an important part of the circuit, it provides the bootstrap current so the alternator can generate power.

I test it with a digital volt meter. for instance. car off. measure battery voltage, should be like +12.6 if its a fully charged battery at rest at 68F. start car, measure voltage again, should be 1-1.5 volts hire than the off reading, like 13.6-14.1 volts. If so, your alternator is working and charging the battery, done.

if you still only see 12.x V or whatever you saw before, put the red lead on the battery + and the black lead on the body of the alternator or its ground screw. do you read 13.8 or 14.1 or whatever volts? then your ground is bad.

switch the car back off.

turn the ignition to II (run) without starting the car. the dashboard red 'alternator' or 'batt' light should be lit. take your volt meter, and measure the voltage from engine ground (fuel rail ground screws?) and the skinny wire D+ terminal on the alternator, you should see about 12V with the key on but the car not running.

if the light doesn't light, or you don't see 12V at the D+, then you need to fix that (dashboard lightbulb, ignition switch and wiring to dash light to D+)

 

Hi:

To answer my question - the small black wire should have been connected to the oil sensor. I went to LKQ Salvage yard and found two Volvo 240 both 1990 and the black wire in the harness is connected to the nipple on the sensor with a brass ring that is on the end of the wire.