Thread: Alternator connections - Def 1998 tdi

I recently acquired a new LR alternator for a TDI. I am having trouble finding any documentation on the connectors and would value some advice.

The old alternator had two wires connected to it. One was a thicker cable and was connected via a screw terminal to the "W" connector (from memory. It was the connector more to the outside of the alternator when bolted in position).

The second wire was a thinner wire on a spade connector (1 of 3 spade connectors on the alternator).

I am assuming the thicker cable is the main cable for transferring charge to the battery.

I have no idea what the thinner cable is for. I don't have a taco, so maybe it is for some kind of indicator?

Anyhow, the new alternator does not have any spade connectors. It just has 3 screw terminals labelled, B,D and W.

Any advice on how to connect up the new alternator would be much appreciated.

Originally Posted by roguecoder

I recently acquired a new LR alternator for a TDI. I am having trouble finding any documentation on the connectors and would value some advice.

The old alternator had two wires connected to it. One was a thicker cable and was connected via a screw terminal to the "W" connector (from memory. It was the connector more to the outside of the alternator when bolted in position).

The second wire was a thinner wire on a spade connector (1 of 3 spade connectors on the alternator).

I am assuming the thicker cable is the main cable for transferring charge to the battery.

I have no idea what the thinner cable is for. I don't have a taco, so maybe it is for some kind of indicator?

Anyhow, the new alternator does not have any spade connectors. It just has 3 screw terminals labelled, B,D and W.

Any advice on how to connect up the new alternator would be much appreciated.

B is the thick battery cable,(Brown big one)should be the biggest diameter post on the back of the alt too.

D is the 'spade' type female plug with a brown and yellow trace wire(Thin)

W is a tacho connection, no use on a defender.

If the W was hooked up to the thick brown wire, you've got problems

No wonder it wasn't charging...

JC