At 07:24 PM 5/18/2012, Bill MacLachlan wrote:
>If you've dealt with this recently you might be able to save me some hard
>thinking with the wiring diagram!

Bill, before you do anything else, check the voltage at the headlight
ground wires at or near the headlights under both conditions.  You
should see voltage in the low tenths, about the same on both
sides.  If you see +12 then that ground is open between the meter and
the chassis.  If you see zero, it's likely open between the meter and
the lamp socket.

I haven't thought it through, but any time multiple-light circuits
start behaving strangely the first place to look is the grounds.

Yours,
David