Hello again,
I have managed to determine that:
a) The plastic relay I was muddling with in the 1990 wagon was, in
fact, the AC control relay (thanks to FCP Groton for the great
pictures) and that the window relay should be the same for all models.
Great.
The remaining question then is, given the voltmeter results I
received, is it a reasonable assumtion that the relay has failed?
Should the voltage across fuse #12 not change when the switch is
employed (as does on fuse #10)?
Or can I start to look for breaks in the wire somewhere?
Thanks a bunch,
blurp