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Thu Dec 20, 2007 8:52 am

Does anyone know the difference? If you are wiring a buggy from scratch would there be any reason to choose one over the other? TIA.

Thu Dec 20, 2007 10:46 am

NONE...... The three terminal flashers I have disassembled just have a separate (external) terminal for indicator lamp that is tied "internally" to LAMP lead.... These are NON VW flashers.

But the thing is how indicator lamp wired, to function properly in flasher circuit...

I personally like three terminal so I can run separate wire from flasher terminal to indicator lamp... Yes its a extra wire/terminal but the simplicity is I know what the wire is for when I have to trouble shoot a problem.... Versus two wires on a single terminal and having to wonder/remember what I did to warrant two wires on same terminal....

Dale

Fri Dec 21, 2007 9:00 pm

I think if you have a single lamp dash indicator bulb you have to use a three terminal flasher to get a separate circuit for the indicator.
You can't just run a wire from the flasher to the indicator light because the indicator light will then always be on (flasher is always "hot" when the ign is on) and you can't run a wire to a single indicator light from both the left and the right turn signal circuits because that would cross-connect the turn signal circuits. (You could possibly do this if you put a diode in each of the wires to the indicator light to prevent back feeding to the other side turn circuit.)
AFAIK three terminal flashers are hard to find now, almost all vehicles made in the last 30 years or so have separate indicator lights for left and right and use only a two terminal flasher.

Sat Dec 22, 2007 5:14 am

Sat Dec 22, 2007 8:54 am

Ahh yes. I keep forgetting VW is different. My bug is being wired with non-VW parts.

Here is the VW circuit showing the internals of the 3 term flasher.

and here is conventional turn signal wiring with two terminal flasher:

and with three terminal flasher:

Notice that none of the terminal in a conventional three terminal circuit is grounded but the VW circuit does have a grounded terminal. I don't know if wiring the indicator light bypassing the flasher would work with a conventional flasher, the indicator light would then be in series with the turn signal lights.