On the 89 Camaro, the harness coming thru the firewall directly behind the passenger cylinder head. It goes to a plug (I beleive C105) Dk Green, Lt Green and Black on the firewall side and then you have two wires on the engine side of this plug. The Lt Blue with Blk goes to the Hi pressure switch on the compressor. The other is a Big Black wire??? Where does it go???

 

Got any pics of it as that will help us out to see what it is. to me it sounds like the HVac wiring but it seems like different coloured wires

 

Added a pic. I think I figured it out. During the LS swap I apparently did not include the Main power wire to the Blower relay and the ground to the blower moter. The black wire is the ground for the relay and blower motor. I can only assume it was back-feeding voltage to this ground, thus why it was showing 6v with A/C control on. I guess my question now would be is where to put this ground? Many places to to put it but I am sure one would be better than another. The hot wire to the relay looks to be sorced thru a fusable link (What size I don't know) directly to the starter or Battery.

So I will sum this question up.
What should be the Amp rating for the fuse to the blower relay and where best to ground the relay and blower motor?

Thanks in advance.