Topic: 1965 mustang heater box?

[racingjz]

hi how yall doing um im looking at heater box in a npd book and they say the heater box are 2 diffent ones  oe with a rheostat hole and with out how do i tell the diffrence thanx

[66GTKFB]

The hole is for a dropping resistor used on three speed heaters. Two speed heaters boxes did not need the dropping resistor or hole. The best way is to look at your existing heater box from the right side under the dash and if there is a four wire cable connected to a red rectangular plate (about 1 1/2 X  2 1/2 inches) on the box you have a three speed requirement.
Jim

[racingjz]

thank you

[Soaring]

I didn't know there was a 3 speed in 1965.  I do know there was a 2 speed though.  That's what mine is. 

[66GTKFB]

Two speed heater blowers were installed in all 64 and early 65 Mustangs. Three speed blowers were a 65 1/2 upgrade. I don't know the exact date but would assume it would be the same as the GT and Pony interior dates.
Jim

[Soaring]

Makes sense.  Good information, Jim.   Mine is a mid year 1965, so maybe a little later than April of 1965 Ford offered the 3 speed.