If you have a voltmeter, you could see which one changes when you move
the thumbwheel.

Larry A.

On 12/24/09, Don Hanson <dhanson928@gmail.com> wrote:
>      I am working on my  new tach. 84 vanagon.  Just installed an
> aftermarket tach yesterday and it works well but the light doesn't go dim as
> I dim the other instruments.  I took the power for the tach light off one of
> two wires that go into the dimmer part of the headlight switch.  White/blue
> stripe in my 84 van.  Up at the multiplug that connects the instrument
> cluster to it's foil circuit board, the Bently says the instrument light
> power comes from a white/blue stripe wire, so I am guessing (not having the
> patience to pull apart the rat's nest of wires in the under dash bundles to
> follow that wire through to the intstruments) I have the proper wire.  But
> maybe I got the supply to the dimmer wheel and not the output from that
> reostat(?)
>
>   So, I have it all apart again today to replace the master cylinder for the
> brakes and I wanted to get the tach light to dim with the other lights.
> There are two white/blue stripe wires meeting in  the headlight switch
> dimmer "wheel".....did I simply choose (and I did just take a chance,
> picking one, figuring I could be right) the wrong one of those two?  Can I
> just move the lead to the tach light onto the other white/bluestripe, or
> could I go up nearer the foil multi plug and get the white/blue stripe up
> there?
>
>   Or should I take some scrap window tint and stick it on the tach gauge
> face...(semi joking)
>
>   Thanks in advance,  Don Hanson
>