[Rust-O-Matic]

That last link is a fantastic thread! I have spent hours searching and reading about this lately and don't know how I missed that. I just got back to this today, and spent all afternoon trying to figure out what I have, what I'm missing, and how the system works, in hopes of getting the blower motor going.

At this point, I understand how the blower fan switch, resistor, and a/c relay work together, but it's not exactly clear why there appears to be two different configurations for each of the two power wires that supply the system.

First, the 12 ga orange wire to the relay under the glovebox is shown in the diagram on my original post to come from a 10 ga gray wire run from the horn relay. Post #7 in that link about dealer installed A/C shows the orange wire running to the starter. Any idea why they used two different configurations? Were the factory made ones run to the horn relay, and the dealer version only run to the starter? It probably doesn't matter functionally, but I'd like to know what's correct. The openings in my dash appear to be stamped from the factory.

Next is the power wire running to the blower fan speed switch. On the diagram in my original post... what the hell is it trying to illustrate for this wire? Why is the ignition switch shown on the left side, and why does this show nothing at all about the fuse box which contains a terminal for heater/AC? The heater circuit on the fuse block appears to be powered by a red (then pink) wire from the accessory position on the key switch, but the diagram doesn't show any of that. What used to be in my truck was very similar to post #6 in the link above. Just a smaller gauge brown wire from the fuse box to the fan speed switch. This is not what that original diagram appears to show though. Again, could this difference be due to the factory vs dealer installation? If so, please refer back to the first question in this paragraph. Ha!

Sorry this is so wordy. I shoulda took more pics while I was rolling around under the dash today.