504 alternator swap confusion

[jonm]

I've just swapped the alternator on my 1980 1800 504.
Old alternator had terminals "m", "exc", "+" and "A+".
New alternator had the m and exc ternminals (not marked though) and "B+", "B-"

Quick check of the haynes revealed "B+" must go to battery (making it equivalent to "+" on the old alt, leaving just the old "A+" wire to go to the new "B-" pole.

Switched on and running, it didn't charge - confirmed by multimeter.

However, when I took the connection at "B-" off, it charged! Put it back on, no charge.

Can anyone with a bit more nous tell me what's going on? I'm a bit retentive, and don't like the idea of riding round with a loose wire and unused terminal.

[jonm]

Answering my own quey, in part, but an evenings frantic research reveals...

what I've done of course, is put a valeo alternator in a car which had a paris-rhone.

Now, I presume, looking at the diagrams, that the valeo has a built in regulator, and the paris rhone didn't, the "a+" lead in being the power for this.

I've got the valeo to work by connecting the "a+" lead at the warning light spade connector, where it balances the voltages when running and turns the light out.

So its charging, and the lights are doing what they are supposed to - however, am I going to burn something out doing this?

[504gld]

I wouldn't have thought so, you have followed through with a multimeter, and as long as the voltage is correct you shouldnt have a problem. Does the 1980 model still retain the volt meter on the dash board? My 504 diesel one shows when the regulator charges the battery, so it varies from low black to high black, and when idle in traffic sometimes red. Keep some spare fuses, older type still available from Halfords, just in case but I wouldnt think you need them.

[jonm]

no, no voltmeter. Like you say, only way to test it is to try it!