Connections go to...?

[Scott91370]

I have an 85 Sierra Classic cab that is going on an 82 Sierra chassis/engine/trans. Everything was unhooked when I got it because there was no engine These wires come out of the fire wall then magically multiply and end in these 3 plugs which I have no idea were they go (Let's say 2, the white square 4 pin is transmission). None of the diagrams I have found show this.








Then there is this plug  that comes out of the firewall directly under the bulkhead connector.  There is a large (vacuum) hose and the connector.  This one I think may be the cruise control but I don't have anything to hook it to compare the connection.  Not sure where it may have gone...


Thanks in advance!!

[Mike81K10]

I your second picture, the top one goes to your oil sensor just above the oil filter. Not sure off hand on the others.

[Scott91370]

Similar plug but my diagram shows it is a 3 wire that goes there with pink/white, dark blue, light blue then the light blue goes to the choke heater once there is pressure.  Which I have found and connected there.  Of course it isn't running so I don't know if the gauges will work.

All this 'extra' wiring is quite confusing.  I wish I could find a truck exactly like mine that hadn't been messed with so I could look under it and take TONS of pictures.

[Mike81K10]

Three wires but only two contacts inside. I believe, two of the wires in the original goes to one of the contacts and the other wire to the other contact. I have only found after market plugs with two wires. Have not been able to find a three wire/two contact plug.