I spent more time than I care to admit on that recycle button
on the dash.  It's backlit like all the other buttons, and
will light when running on VO.  I'm connecting this button and
the LED's that are behind it to a BASIC Stamp microcontroller 
that has a temperature sensor which will go on the VO filter.  
The Stamp will then control the startup and shutdown of the VO
system pretty much automatically (with the button being
the 'manual override').<br>
<br>
I have that functioning perfectly on the workbench, but have yet
to get it installed.  Until then, I have an ugly piece of 4mm 
plywood with two big switches mounted on it stuffed into the 
ashtray.  When the temperature guage reaches 190, I switch to VO.<br>
<br>
Another think I've done is a nice little hack by Jamie Braman who I met on the
Greasecar forum.  When the system is runnng on diesel, the fuel gauge
under the speedometer shows the diesel level.  When running on VO,
the fuel gauge shows VO level.  That way I didn't need to mount a
big secondary fuel gauge anywhere -- very slick.