Heater Wiring - Please Help!

[truckster]

I'm rewiring my Blazer (72 CST w/AC) and there are some things I can't find on the wiring diagram I'm using. This Blazer has been apart for seven years, so I don't quite remember all the details of how it was put together. Aside from that, the PO had hacked the wiring harnesses to bits, which is why I'm rewiring it in the first place.

In the first pic, I believe the brown wire goes to ignition fused.

In the second pic, there's a relay on the right side of my heater box (the relay isn't shown on my wiring diagram) and it has a heavy orange wire. I believe this one is also ignition fused.

In the third pic, there is a connector with green and yellow wires behind the heater box. It's not really long enough to go anywhere, and I can't figure out where it's supposed to connect.

Your help is greatly appreciated.

[Pro299]

It's been a while since i put mine together (72 C10 w/ac), but I'll try to help.

I don't remember about the brown wire, but the heavier gauge orange on the relay as i recall goes directly to the fuse box to supply power when the fan switch activates the relay.

The dongle on the third pic looks like the one that goes to the compressor switch located on the back side of the airbox right below where it is in the pic. You can't see it from the interior because it is between the AC and heater distribution boxes. The switch is mechanically activated by the same cable that operates the air flapper between the heater and AC. If you reach behind the AC box you should feel it from below. Unless a PO removed it, of course.

Hope that helps, and if I've remembered wrong I'm sure someone can correct me.

[truckster]

Thank you. Both of those sound correct.

[sick472]

The orange wire is the power feed for the "High" fan speed. It is connected to the plug that goes to the "Cig" spade at the fuse box. This will help you out...

[truckster]

Thank you.