suggestion
Early 1965 ( 64.5) had the Pressure switch on the Master cylinder under the hood. Like this one. If you replace it be sure and buy the "LOW" pressure type which is available from most auto stores.
Later 65's had a mechanical switch on the brake pedal like this one:
And must be installed correctly;
Here is a diagram of switch
Hope this helps.
Joe
Early 1965 ( 64.5) had the Pressure switch on the Master cylinder under the hood. Like this one. If you replace it be sure and buy the "LOW" pressure type which is available from most auto stores.
Later 65's had a mechanical switch on the brake pedal like this one:

And must be installed correctly;
Here is a diagram of switch

Hope this helps.
Joe