(Electrical) Heater/Fan Wiring

[Boydness]

Another missing/possibly hacked wiring issue...

What color is the wire that runs to the fan connector in the engine bay?
The connector is bare and the other ground(?) connector has a black wire to ground.

If anyone has a wiring diagram or tell me how it is to be wired, I would appreciate it.

Can anyone recommend a heater control lever rebuild kit for the 3 levers on the dash controls or have a good used one for sell?

Boyd

[Stocker]

Originally Posted by Boydness

What color is the wire that runs to the fan connector in the engine bay? The connector is bare and the other ground(?) connector has a black wire to ground.

Had to rub off many years of neglect, but mine is a dull reddish color. It comes out of the wiring harness about 5 inches from the connector. hth!

[VetteVet]

Originally Posted by Stocker

Had to rub off many years of neglect, but mine is a dull reddish color. It comes out of the wiring harness about 5 inches from the connector. hth!

Mine is in the same place but it is orange.

[Boydness]

Originally Posted by VetteVet

Mine is in the same place but it is orange.

Wiring Harness?
I don't have any wiring harness near it. The cables from the fuse block end at the coil. I don't have anything that extends that far. I do have a red cable coming the long way around the engine bay (across the radiator support) that connects into a fender wall stud connection thing that then runs to the positive battery terminal.
Does it come from inside the cab? I did find a cut red/orange color cable, coming from a connector with Pink, Yellow, and Blue cables. I do have a hole in in the firewall that it could run through to reach the terminal. I would guess that would be it or is that for something else?



Boyd

[69TowRig]

The fan runs off a single wire that comes out of the firewall on that side. Inside the cab I believe it went to the fan resistor plug. I'm about 500 miles from my truck at the moment so I can't check for you. The current thread about engine colors has a couple pictures at the bottom right now that you can see the orange wire going to the firewall:

http://67-72chevytrucks.com/vboard/s...d.php?t=178397

[pjmoreland]

There's a connector under the dash that plugs into the top of the heater box underneath the glovebox. The connector has four wires (three contacts) coming out of it (yellow, light-blue and two oranges). One of the two orange wires is supposed to run through the firewall on the passenger side right next to the heater motor. There should be a black rubber grommet molded onto the orange wire to seal the hole in the firewall. The orange wire connects to the heater motor.

These wires are all part of a small wiring harness that is powered by a brown wire connected to the fuse panel. The wiring harness runs between the heater control switch on your dash to a group of resistors mounted in the heater box, and then to the heater fan motor. The resistors give you the different heater fan speeds.

[Boydness]

Originally Posted by pjmoreland

There's a connector under the dash that plugs into the top of the heater box underneath the glovebox. The connector has four wires (three contacts) coming out of it (yellow, light-blue and two oranges). One of the two orange wires is supposed to run through the firewall on the passenger side right next to the heater motor. There should be a black rubber grommet molded onto the orange wire to seal the hole in the firewall. The orange wire connects to the heater motor.

Sure enough, that wire was the one for the fan. I spliced in an section of wire and a connector and ran it through the firewall. Why would someone cut the wire and remove it and the grommet? If the fan worked, why cut the cable and remove it?

I fabbed a switch and tested it from the connector at the 3 lever control panel. I have high and the other 2 speeds, the motor sounds fine.
The three levers are all broken and all the pull cables are pretty much stuck. All the backends of the levers are as close to the driver's side as I can get them (I pulled them as far as I could, WD40 does not help). Is that defroster and heat?
The heat is the important part. I can get the fan to high with my fabbed switch, and I think that I have it in defroster position now (I feel the air coming out of the top of the box), but how can I tell if the heat is in the correct position? The cable runs inside of the box, I pulled back the grommet, and can see it attched to a stud(?), I think that it is a fixed point, because I can not seem to get it to move.

Any ideas?


Boyd

[pjmoreland]

Is there a chance your heater box is packed full of leaves or pine needles?

I noticed that www.gmcpauls.com sells steel heater control levers. They will be way stronger than the original cast aluminum levers.

[Boydness]

Originally Posted by pjmoreland

Is there a chance your heater box is packed full of leaves or pine needles?

I noticed that www.gmcpauls.com sells steel heater control levers. They will be way stronger than the original cast aluminum levers.

Were you watching me clean it out? :LOL:
I think that they must have been in that fixed position for some time. I think that I got everything out, short of uninstalling it and cleaning it.

Do I have I have everything in the right spots for defoster and heat?
I will probably go with the rebuild kit that the have, after I figure out were/why the heater lever cable is binding up.

[pjmoreland]

On a fully functional heater control, all three lever knobs to the right will give you maximum heat through your defrosters, which is the same thing as pulling the back ends all the way to the left. Sounds like you have them in the right position.

Be gentle on those levers. If you push too hard, the portion that holds the levers will end up popping off the faceplate and you'll be hunting for a drill and pop rivets to fix it.

[67chevemall]

I just use a toggle for the fan(high speed)
And the cables are all gone too! At the end of the cables are
steel levers you can just adj. One for the heat on the bottom(switch once
a year) And the Def Floor is right out in front!
Simple and less parts.

$0.02