A pink wire from the "Ign" cavity in the fuse block goes to one side of the switch, and a pink wire from the other side of the switch goes to the coil in the relay; the relay coil grounds through the case tab, where it's screwed to the firewall. When the switch is closed at WOT, that sends 12V to the relay coil, which closes the points in the relay. One side of the points has a tan wire to the fuse block (power), and the other side of the points has a tan wire that goes up to the solenoid in the hood, which is grounded through its attachment to the hood. When the relay points close at WOT, that sends 12V through the tan wire to the solenoid, which energizes it and opens the air valve. If you don't have a good clean ground where the solenoid is attached to the hood, it won't work. The reproduction throttle arm switch is junk - the GM switch works fine.
OK John, I am with you up to a point. I have a pink wire running from the fuse block IGN to the switch and then from the switch to the relay. I have a tan wire running from the fuse block ACC directly to the relay. the relay has a three prongs. the tan wire stands alone on the passenger side of the relay. the pink wire is in a two prong "T" shaped fitting and plugs into the driver's side prong while a black wire connects to the center prong (using the same "T" shaped plug) and leads to the solenoid.
When the key is the run position the tan wire is always hot. Mostly the black wire to the solenoid is hot (12V) but occiasionally the switch seems to interrupt the current (the occaisionally part is the bit that makes me think the switch is bad). Does this configuration sound correct to you?
I don't own any cars with cowl induction so have never had to mess with it. This car was not originally equipped with the the cowl hood (as the firewall was not drilled for the wiring harness - instead it was fed through the clutch rod hole) but someone seems to have collected all of the parts (I don't know if the are correct or good parts) such as the flapper door, seal, throttle arm with fitting for the switch etc.
From your discription it sounds as if I should not have three wires at the relay and that I should not have two sources of power there. Any further light you can shed on this would be reatly appreciated.