B61 Defroster Circuit Diagram

[58GreenMackB 15]

I am looking into replacing a switch for the defroster circuit on a B series.  I know the original switch was a 1 ohm 3 position switch, but need to see a circuit diagram to find a suitable replacement.  Does anyone know where I can find one for the defroster circuit?

[j hancock 13,661]

May want to check with the Mack Museum for a diagram.  I looked at a couple of B wiring diagrams and neither listed the defroster circuit.

[58GreenMackB 15]

What’s the best way to contact them to get this info?

[j hancock 13,661]

Here is a link to their site.  Could email them.

https://www.macktruckshistoricalmuseum.org/

[41chevy 10,223]

My B61 the switch for the heater fan is the same switch for the defroster fan. Yours different?

[58GreenMackB 15]

A switch on the left side of my dash was replaced with a toggle switch, but I saw that some like mine had an extra hole with a knob I couldn't identify.  I found out through researching various pictures of B series that there was a defroster switch in that hole.  I will get the information from the Mack Museum to find out more about the switch.  Not 100% sure it originally came on my truck.  Even if it didn't, I will pass the knowledge onto others.  It is my goal to return my truck with some minor upgrades to as close to original as possible.  Always fun to learn something new.

 

Edited February 27, 2018 by 58GreenMackB

[Mike Stormo 7]

following

 

[Freightrain 2,490]

http://www.wattstruckcenter.com/store/index.php?route=product/product&path=59_71&product_id=378

Here is the switch and it has the resistor built in for the 2 speeds.  No other wiring should be needed.

[Maddog13407 2,174]

only the B series with the bigger heater with separate defroster fan had the switch and most i have seen were back wired right off the heater switch. i don't think there was a separate circuit for the defroster.