Ha! I think I've finally got the headlight/high beam relay switching figured out.

First - Credit where credit is due:

Art - the two high beam relay pix. This explains virtually everything.

The OD Guru (Duane) - let me borrow his wiring Green book. What a revelatory document.

The problem I was having was with the wiring diagram in the Bentley manual (I realize, of course, that it's just a black-and-white copy of the Volvo wiring diagram).

Specifically, my problem was with the way the high beam relay is drawn - it looks like it has sort of a DPDT switch function - well, actually, more like a SPDT switch function in parallel with a SPST switch function. If this were the case, it appears that in the relaxed condition, terminal 56 is connected to terminal 56a, and terminal 81a is "connected" to an open circuit. In the energized condition, terminal 56 is connected to terminal 56b, and terminal 81a is connected to an unidentified terminal (which is permanently connected to terminal 56a).

But - after seeing Art's photos of the relay sans cover, and looking at the circuit in its active forms (Green book), I now realize that only the 81a switch is activated by the relay coil. Each time the relay is energized, the rod (or arm or whatever it's called) mechanically switches terminal 56 between terminals 56a & 56b. Power comes in through terminal 56; high beams are connected to terminal 56a; low beams are connected to terminal 56b.

Since the stalk (in the steering column) controls a momentary switch, and this switch provides the ground to active the high beam relay, this is how the high beams and low beams are switched on and off by "just" pulling on the stalk.

And since +12V is hard wired (from the battery) to the high beam relay, this is why the high beams will flash when the lights are turned off and the stalk is pulled.

Seeing the wiring reduced to the circuit in question (via the Green book) makes all the difference. Duh.

Any corrections?

As I progress with my little exercise of re-drawing the wiring diagram in Autocad 2000, I will be drawing the high beam relay - as well as a number of other components - differently.