620 heater/fan issues

[perrydime]

This is my first post, so please bear with me-

 

The heater in my '74 620 randomly stopped working about a week ago. The fan has never worked (I bought the truck Nov. '09), and I've relied on the air being forced through the vents by the truck being in motion (extremely ghetto, I know). The heater core seems to be fine, it doesn't leak or anything. I did find that the cable from the fan switch is not attached to anything, and I assume this is why the fan doesn't work.

 

Anyone know what the cable is supposed to connect to?

 

Any ideas on why the heater stopped working?

 

Also, does anyone have pics of the heater controls? My dash is missing some pieces...

 

Any suggestions would be greatly appreciated.

[datzenmike]

There are two top controls that slide side to side and a large black knob just below them that pushes in and out only.

 

The topmost slide moves from the left (OFF) position to the center (DEFROST) to the full right (HEAT) and operates a cable that opens a flap door on the bottom of the heater unit to let the heat out into the cab.

 

The second slide does two things: it opens and closes an in line water valve allowing more or less hot water into the heater and by pulling outward two positions turns on and gives two fan speeds.

 

The large black knob pushes in to allow heated or vent air direct access into the cab.

 

If you had warm air and now you don't then the cable attached to the bottom slide must have come off the water valve when it was in the closed position. If you work the bottom slide lever and look at the bottom passenger side of the heater assembly by the floor you'll see the hoses and a brass valve. You should see the cable wire with a loop in the end moving and nearby a small lever to the water valve, just slide the loop over the end to get it working. If the cable is on but not moving perhaps the other end is off, but harder to get at. Just work the water valve by hand into the open position. This gives full heat only and no control.

 

If there are fan wires at the lower slide switch look for a plug up near the top of the heater on the driver's side above the gas peddle. There should be a Blue power wire going to the fan motor. Check the cigarette lighter... if not working with the key on the fuse may be blown.