the car is a 1986 Firebird with the LG4 305. The E4ME is off, ECM and harness removed as are all HVAC components and I'm tracing and labeling the engine and HVAC harnesses to trim what remains down to the necessities. Now, I get to tracing the wires at the fan relay and I run into some major confusion. I don have a thermal switch for the fans in the cylinder head and I thought all the V8 cars did. Likewise, the wire information I found on the car looks like this:

Terminal A: Blk/Red (to fan)
B: Green (to fan switch)
C: Brn/Wht (bulkhead connector G7. what is this wire's purpose?)
D: empty
E: Red (hot wire to B+)

But, my car looks like this:
A: Blk/Red
B: Green (goes through bulkhead with HVAC harness on P/S)
C: 2 wires in one pin, Brn/Wht, 1 goes into G7 like above but the other goes
to the AC relay by the right headlight/battery.
D:Red (hot wire)
E: empty
Is the fan controlled by the ECM on this car?

The connector at the fan relay has been replaced it seems but the harness is otherwise unmolested. I'm not 100% sure that the fans worked prior to me disassembling the car. I didn't drive it much after I bought it before I started working on it but I never had any issue with coolant temps when I did.
What is the correct P/N for the fan relay on cars WITH the thermal switch in the P/S cylinder head? Mine doesn't seem to have been replaced but with the differing pin assignments for D and E I don't see how it could be the same. With the correct relay I'm thinking I should be able to swap locations for pins D and E, move the green wire to the new thermal switch, and with no HVAC I should be able to remove the extra wire in pin C that goes to the AC relay.

If you followed and are patient and have an idea of what's going on, please help. I've never been in these 3rd gens before but I'm neck deep in this one and the learning curve is getting steeper.

And what does the brown/white wire in Pin C feed power or a signal to?

 

+12v ign switched to power relay coil, fan switch grounds coil causing relay contact to switch.

 

Makes perfect sense. I should have known seeing that it is also fed voltage from that AC relay as are several other components to be switched on with the AC.
Since the thermal switch on the head normally is the control device (provides ground) for the control circuit for the fan relay but the green wire disappears into the bulkhead it seems pretty reasonable to me that my fan was controlled by the ECM. By simply installing a thermal switch in the head (there is a brass plug where it would normally be) and moving that wire to the switch it also seems reasonable to me that the fan should work with no other changes to any other circuit as if the ECM was never removed. Someone else just back me up on what I think I already know. I'd feel a lot better about moving on with it, but I can't find any holes in it as it is.

 

Sounds about right. The going through the bulkhead is most likely leading to the hvac controls... any a/c setting would also ground the (green wire) relay, like a Tbi car does. Key on and touching green wire to ground will verify if is fan relay control or not.