Alternator/regulator prob

[therealchrisgray]

Hopefully this is an easy one for the experts here, you guys are usually amazingly helpful...

I had a squeaky fan belt for a while, then it went quiet and I started to get a battery warning light. I've replaced and retensioned the belt but the warning light persists and this morning it wouldn't crank over fast enough to start.

I swapped out the battery for a nearly new one, engine started immediately. Multimeter read 12.4v with engine off, 11.5 with engine running. So I deduce the alternator is not providing power.

After perusing the many related threads here I went back and looked for the blue excitor wire, but that doesn't appear to exist. I did find a red one that looked to be broken and a spade connector that looked like it previously had a red wire attached. Photo below, connector circled in red after I removed the spade grip.

Have I reached the right conclusion? Can I test it by just holding the red wire to the connector to see if the voltage goes up or is there more to worry about? Have I knackered it by not tightening the fan belt soon enough? Or was the squealing due to some increased load or something as the alternator was dying?

Engine is probably an AAZ, logbook doesn't say, 1.9l diesel. I can't see anything on the alternator to identify make/model/output.

[Forden341]

I think the 2 terminals shown with wires attached are probably the battery +ve (m8) and the exciter wire (m6 bolt appears to have a blue wire?)
I think the spade may be a W terminal for the tacho feed on a diesel possibly.

[therealchrisgray]

I think the spade may be a W terminal for the tacho feed on a diesel possibly.

Ah, so not useful now then? Any idea what the red wire might be? There doesn't appear to be any current flowing through it.

The big one goes to the battery, correct, and voltage at either end is the same so I guess there are no breaks in it, etc. Are those the only two wires I should have?

I revved it up to "loud" (no tacho) and got 14v from it. Could the problem just be belt tension? I saw someone else having trouble with this. It's "finger tight" now but does seem to jump about a bit still. Should I try to get it tighter?

Thanks

[Mocki]

[therealchrisgray]

Thanks all, new brushes seem to have solved it.