Thanks for the advice Pizza.... yesterday I had another go at the PW. I had someone help me by pushing the PW buttons while I measured voltages at the relays, relay grounds, switch feeds (#38 right PW, #39 left PW), and wires running to the PW motors (#10 Passenger PW down, #11 Passenger PW up). There are definitely only 3 relays. And all 3 seem to have a part when any PW button is pressed. All 3 have posts where voltages change when the passenger PW down is pushed (and for the rest of the functions). And all 3 feel/sound like they're doing something when a PW button is pushed. The switch feeds had identical voltage changes compared to eachother, which would indicate that the switches are good. For good measure though, I swapped switches inside but the same condition still persists.

I then removed the BCM from the car per the service manual. I opened it up inside so I could examine the solder connections with a magnifying glass but everything looked kosher. I have access to the probably the crappiest soldering iron in the world and I didn't want to get all ***** nilly and start throwing it on every connection I saw (BCM is expensive and I don't want to mess it up). I also checked the male/female posts in the BCM and plug on the car for corrosion. Everything looked good. Also, when I first had the door apart originally, I hooked up the new regulator to the harness in the door (didn't actually install it in the door because I wanted to see if it worked first) and still got a clicking from the relay.

BTW, when I reinstalled the BCM and started the car, the spoiler button is blinking now. The battery is newer and I'm getting 12.0-12.4V while the cars off and about 14.4-14.6V while running. I did try leaving the (-) battery cable unhooked for about 10 minutes and hooking back up but it's still blinking.

But I definitely suspect there is something going on in the BCM. Probably like you said with the solder connections. I'm going to have to buy a good iron before I do that though.