New alternator not charging.

[davidc89]

Greetings all!

I replaced my old Ducellier alternator out with a new one from one of the vendors. I got it installed and now it isn't charging. I checked with a multimeter at the alternator and confirmed it wasn't charging. I hooked up the brown/yellow wire, from the old connector, to the brown wire on the new alternator connector. I cleaned the connections that attach to the post on the alternator as well. From what I read, the other wire on the Ducellier connector does not go any where. Maybe I am missing something?

Any help would be appreciated!

[DMC5180]

The brown wire was the 12V sense wire. If you had a pigtail harness plug for the new alternator with all the tails in it, you could connect it to the “S” terminal. It’s technically not required for the DMCH units but it does work. FYI, brown wires are B+

[davidc89]

The connector, for the new alternator, had all the wires cut except the brown wire. I got it from deloreango.

[DMC5180]

Yeah, that’s typical when you get it from a D vendor. Like I said, it not required for the Alternator. The internal regulator are connected internally for the sense. Downside is that the external wire provides a more realistic voltage level for the car because is shows any voltage drop. Then the regulator would compensate accordingly.

Have you tested the Brown/Yellow wire for voltage? Do you get a Pulsating batt light with the key On?

Like this, it’s my car with DMCH C130 Alt.

https://youtu.be/rNaoxycxAVA

[davidc89]

I have not, I will check. If it doesn't have voltage, where does that wire go? I don't think I have a battery light pulsating... I'm not sure my light has ever worked. Might be burnt out.

[DMC5180]

I have not, I will check. If it doesn't have voltage, where does that wire go? I don't think I have a battery light pulsating... I'm not sure my light has ever worked. Might be burnt out.

A functional BATT light is required. I believe if you ground Brown/yellow wire, it will make the the light come on if the circuit is good. I’ll check the wire diagram to confirm though.

Go to the RESOURCES section > All Wire Schematics. First post, second diagram.

[Ron]

A functional BATT light is required. I believe if you ground Brown/yellow wire, it will make the the light come on if the circuit is good. I’ll check the wire diagram to confirm though.

That's right.


...and you don't want to use a LED for the BATT light.

[davidc89]

Looks like I will have to check that the battery light in the dash isn't burnt out. I'd imagine I'll be taking the binnacle out

[DMC5180]

Looks like I will have to check that the battery light in the dash isn't burnt out. I'd imagine I'll be taking the binnacle out

Make sure the bulkhead connection in the engine bay is good. It never hurts to exercise the connections. It will help rub new contact areas in the terminals. Also look for pins that could be pushed back. Pull fuse 5 and make sure it’s good. A simple 12v test light is good to have for probing for power. A DVM continuity test between Fuse 5 and the Brn/ yel wire at Alt, should tell you if the circuit is good or not. These cars are 40 years old. Frankly I’m surprised yours still had the Ducellier Alternator in it.