What is this? Gratuitous dirty engine pic!

[Funstuie]

I’m trying (and struggling) to clean up the wiring in my 76 C10 and as I trace all the random crap that’s been added over the years it’s rhe stock looking stuff that’s starting to confuse me now.

The wires go through the firewall and to the fuse box but don’t seem to be connected to anything so I don’t know what this is:

I can’t seem to rotate the picture.

[Funstuie]

This work?

[mongocanfly]

HVAC fan....

[Funstuie]

Originally Posted by mongocanfly

HVAC fan....

Ok. Thanks. Hvac doesn’t work on this truck.

[mongocanfly]

This is the fan...

[dmack91]

The yellow, orange, and blue wire set run to the heater fan switch. That connector on the fan switch also has a fourth, Brown wire . That wire goes toward the gauge cluster where it connects to a Brown power wire in the harness.

[Dead Parrot]

Only the flat ribbon going through the rubber thing will show up in the cab.
The middle T shaped connector goes to a resistor setup that is in the airway.
The single wire is the hot wire for the fan motor.
IIRC - there should also be a ground wire from one of the motor screws to the cab. If that one is missing, could be why the fan doesn't work. If the fan housing is metal, may not need the ground. AC trucks have a non-conductive fiberglass type fan housing. Not sure about heat only trucks.

[Funstuie]

Thanks for the responses all. The previous owner seems to have disconnected lots of stuff. The horn is disconnected, the wipers and window washers are disconnected and as I've discovered in this thread the heater blower is disconnected.

The wipers work so I can wire that one back up (I tested it last night and they work so I don't know why that one was disconnected). The horn is in the engine bay but there is no wires going to it and there are no wires in the column but there is a wire connected to the fuse block.

I will have to try work out whats going on with the blower motor.

[Palf70Step]

horn wire is in the bundle for the turn signal. Should be a black wire. The one to the horn I believe is green and in the wire bundle for the headlights. There should be a horn relay, I think in upper left corner area of fuse block where the wire to the horn runs from that ends up in the turn signal bundle. NO telling though. My favorite saying down here on every old truck is that it seems the prior owner used started a lawnmower under the dash, then grab several rolls of duct tape to fix it.