Ford heater box

[416Ford]

Trying to get the defrosted to work in the Strretrod this winter. I sold the original one and this one is out of one of the parts cars. Not sure of the year. I am assuming that I need to have a reverse polarity switch for the fan and I would need to have one or more of the doors open on the front of the box to get it to work.
I was recently told that Ford never used a reverse polarity switch so I was doing something wrong..... I don't see another option, this is why I am asking for help.

[416Ford]

Or does all the heat come out the back side? and I have the fan going the wrong direction?

[58 Yeoman]

IIRC, wouldn't you just shut the front doors which would  force the fan to push the air up the defroster hoses?

[UGLY OLDS]

My kid has one of those in his '37 Dodge ....It will melt your shoes .....

  Here's the scoop.....
For Heat....Open the doors on the front & turn the blower on ...Air blows through the core & out the front with the doors providing direction....It is strong enough to heat the back seat .......
 For Defrost ......See the two large pipes/tubes  in the back by the blower  They get connected to the defroster ducts at the base of your windshield with a/c duct or convoluted tubing ...The little flappers connected to the little link in the second picture controls defroster airflow ...close them..No defrost ..Open them..LOTS of defrost ....The fan for the defroster just sucks warm air from around the heater area ...Not very high tech BUT very effective ....Don't overthink this part....Remember..It's an old car...

  When i built his heater, I used a new motor from NAPA... One speed 12 volt ...I mounted  an ignition resistor INSIDE the blower area ...Used a 2 position switch ..first click goes through the resistor giving sorta 7ish volts to the motor & comfortable airflow in both heat or defrost ......( See above..You need to pick..) The air blowing in the housing has kept the resistor cool since about 1988ish..
The second click gives full 12 volts to the motor causing skirts to billow, hats to blow off & INSTANT heat to all in the car ....    

 Give me a call if you need further instructions ......

Bob...

[416Ford]

I have it set up like that now Bob and it doesn't work.
The cold air comes in the back threw the fan into the radiator and into a closed off box, then gets forced back threw the radiator against the incoming air then thew the fan that is pushing into the box past the cold air and up the defroster tubs.  


The defroster tubes are behind the fan on this set up.

[416Ford]

Bob, I am getting what you are say and I am wondering if we can bring it into the 21st century by using a reverse polarity switch then?
Will the NAPA motor have an issue or will is be fine running in either direction?
Seems like the heat would have a better chance of going up the tubes if the door was open and sucking air up the tubes directly.

[416Ford]

Well I did not figure it out but I did do a search on the BARN and I now have the answer. Looks like Ford really did have some good ideas back in the 40's.  Forward and Reverse fans.
https://www.fordbarn.com/forum/showthread.php?t=207753&highlight=defroster

[UGLY OLDS]

Well I did not figure it out but I did do a search on the BARN and I now have the answer. Looks like Ford really did have some good ideas back in the 40's.  Forward and Reverse fans.
https://www.fordbarn.com/forum/showthread.php?t=207753&highlight=defroster

  That's the heater you have ...But to make it work, it must have a 6 volt REVERSIBLE motor ...( Think how a power window motor works electrically--The switch reverses the motor polarity to change direction) ...You also must have the proper fans & housing parts ...

Bob..

[416Ford]

Bob, I have the replacement 12 NAPA motor in the car. I can hook up a reverse polarity switch and a two speed switch. I think I will test it before I put the glove box back in so I can see if I need to block off any of the open area.
I should be all set now.