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Just putting my alternator back in after a rotor change and I noticed that one of the leads may need to be replaced. It is not the power but the second lead; the one on the centre terminal (20-22AWG cable) that disappears into a harness.

The cover on the cable has worn through in a couple of places. What is this cable called and where does it go? Is it easy to replace?
 

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I believe that the cable I am talking about has been described as going between D+ and the Dash Light. Any idea if this goes directly there or how it is routed? Ideally, I would like to replace this.

I also noticed that there is no cable to connect to W on the alternator. Is this correct or has it fallen somewhere inside the engine compartment?

This is for a '98 HSE with a Magneti Marelli alternator.
 

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If there is bare wire showing, id replace it asap, but even if not, better safe than sorry
I i remember correctly, my alternator only has one wire connected (to the bottom terminal). There isn't one connected to the top. When I get home i'll double check it
 

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Thank you for your help.

Any update? I would really like to change this wire out as there is bare copper showing in a couple of places but I would like to have some idea of how difficult this is.
 

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Sorry for the delay

Here are a few pics of where the wires connect to the back of the alternator. Note that this is an aftermarket alternator, so the connections may be different



Labeled (from top to bottom) B+, D+, W
Last plug is unused



If there is bare wire showing, i'd replace it straight away, if anything touches it there could be a short. That said, i'm not sure how hard it will be to replace, you'll have to trace the cables to find where they go. One should go straight to the battery, and I believe one goes towards the BeCM (as the tacho reads from the alternator somehow... found that out when my tacho went to 0, followed shortly by a complete failure of all the electronics)
 

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This is interesting. In addition to the power (B+) cable, you use the D+ screw.

I am connected to the B+ and W+ screws. I wonder who is correct?

I have been using this as a guide:

http://forums.lr4x4.com/index.php?showtopic=6489

where it says:

W+: rev counter

B+: Main output - normally connected directly to the positive terminal on starter solenoid. From there there should be a thick gauge cable to the positive terminal on the battery

+: Not to be used in a normal LR setup. It is the radio suppressor capacitor, connect between 1uF and 4uF to this terminal and connect the other end to earth. On most alternators + is internally connected to B+, a separate terminal is just provided for convenience. Suppressor caps usually come with a Lucas blade terminal to connect to + and a earthed tag which is fitted under one of the body through bolts.

D+: Charge warning lamp. Actually the charge warning lamp is connected to the positive terminal on the battery (from a ignition switched supply) and the D+ terminal on the alternator. When the engine is started current flows from the battery through the charge warning lamp through D+ on the alternator and from there through the windings to vehicle earth/ground/negative. This current is needed for the alternator to excite itself (field windings) so it can begin to produce current itself. When the alternator begins producing current the D + is producing current, and therefore sending current to the charge warning lamp. The charge waring lamp will then receive positive current from both battery and D+ and will therefore not light up.
 
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