alternator wiring????? Topic is solved

gh · Post by gh » 17 Jan 2006, 19:31

how many wires need to be connected to the alternator on a 86 240 dl. I have 3 terminals and only two wiresa attached. I have a third one with a busted connecter. Is there a ground wire on this alternator or are all three hot?

Guest · Post by **Guest** » 17 Jan 2006, 20:43

the big red wire goes on the big post, the small wire goes to your idiot light and gives your alternator the initial current that starts it charging it is connected on another connector close to the big post. The ground wire runs from one of the alternator case screws to a bolt close by on the engine. I am doing this from memory please consult a wireing diagram before you burn out a very expensive alternator.

gh · Post by gh » 18 Jan 2006, 03:34

I forgot to add that all three wires are red. Now, the one with the busted connector is touching some metal. Will this cause a short in the system and drain my battery?

LaRy · Post by **LaRy** » 18 Jan 2006, 10:43

It should just be one thick red wire connected to a big post B+ and a thin red wire connected to D+, the "idiot light". Then you also have a capacitor connected between the big post B+ and the ground, housing of the alternator. Nothing else is needed. In some cases I have seen a white-red wire connected to W. In electric drawings it is used in Diesel versions. It could be temperature feedback from battery, very seldom used.

gh · Post by gh » 18 Jan 2006, 13:43

I had a mechanic friend of mine lok at the wiring to the alternator and figured out that the wire was wrapped in a red shrink wrap. It is actually the ground wire (green wire). Now I'm wondering if the wire not being connected could case a short in the system and discharge the batery. Is this possible?

LaRy · Post by **LaRy** » 18 Jan 2006, 15:06

This capacitor is just a noice supressor, killing small sparks in the sliprings. On the other hand, it must be some reason why it is disconnected. Your problem has maybe been there for a long time and if a bad capacitor with internal short circuit is connected, it will discharge the battery.

Anyway, a capacitor should be installed, because those small sparks at the sliprings could destroy the electronic in the charging regulator.

gettingrepairsinfo · Post by **gettingrepairsinfo** » 05 Dec 2015, 11:11

LaRy wrote:This capacitor is just a noice supressor, killing small sparks in the sliprings. On the other hand, it must be some reason why it is disconnected. Your problem has maybe been there for a long time and if a bad capacitor with internal short circuit is connected, it will discharge the battery.

Anyway, a capacitor should be installed, because those small sparks at the sliprings could destroy the electronic in the charging regulator.

Hi LaRy, Please let me know if you think it is a good idea to have a resistor in between the B+ post and the capacitor. I see the bigger alternators have a plug in the back and don't use the same connector to the B+ post that the small alternators have got.