W-terminal

[wolfsburged]

I have an 84 Jetta TD that is now recently back on the road. I have another mk1 cluster with tach that I want to swap into my cluster.

It is my understanding that cars with the upshift light have the w-terminal alternators that can be used as a tach signal. My car has the upshift light and the huge reverse switch. Do I have a w-terminal alternator?

[Patrick]

As far as I know, it should be there. Look at the back of the alternator. There should be one wire that plugs into the back of the alternator separate from the rest. It will be labelled with a W, probably cast into the case.

[Kantdrivefast]

That tach wont just hook up fyi.... you will need to do some re-wiring or use a decoder box.

Could just put a mk2 cluster in too...

[Vincent Waldon]

I have another mk1 cluster with tach that I want to swap into my cluster.

Just to clarify... if this is a diesel mk1 cluster/tach then yes, all you need to do is hook it up to a w-terminal-equipped alternator.

If it's a gas tach however the signals are incomparable... there are threads in the FAQ on various conversion options.

[Kantdrivefast]

I have another mk1 cluster with tach that I want to swap into my cluster.

Just to clarify... if this is a diesel mk1 cluster/tach then yes, all you need to do is hook it up to a w-terminal-equipped alternator.

If it's a gas tach however the signals are incomparable... there are threads in the FAQ on various conversion options.

As far as I know there were no A1s diesels with tachometers. I've got an 84 as well as an 81 and neither came with a tach. Although, the 84 does have an upshift indicator.

[Patrick]

An early mk 2 cluster should work..........  Might need the harness that goes to the cluster from the fusebox too. Just checked my stock, have a late (1984)mk one diesel cluster (no tach) and an early (1987?)mk2 cluster (tach) plug looks different.

[Kantdrivefast]

An early mk 2 cluster should work..........  Might need the harness that goes to the cluster from the fusebox too. Just checked my stock, have a late (1984)mk one diesel cluster (no tach) and an early (1987?)mk2 cluster (tach) plug looks different.

Any mk2 cluster you use, you will have to have the harness for the cluster and splice it into your wiring...

[wolfsburged]

Here is my alternator. It is a Bosch AL22X. I believe the bottom red wire is going to the W-terminal?

[Vincent Waldon]

Yuppers.