cocoa nstextfielddelegate EXC_BAD_ACCESS

Question

I'm trying to hook a NSTextField to a NSTextFieldDelegate to implement the controlTextDidChange.

// TFDelegate.h
#import <Cocoa/Cocoa.h>

@interface TFDelegate : NSObject <NSTextFieldDelegate>

@end

// TFDelegate.m
#import "TFDelegate.h"

@implementation TFDelegate

- (void)controlTextDidChange:(NSNotification *)notification {
    NSLog(@"controlTextDidChange");
}

@end

// ViewController.m
- (void)viewDidLoad {
  [super viewDidLoad];

  TFDelegate *del = [[TFDelegate alloc] init];
  [self.TimeInput setDelegate:del];
}

As soon as I start typing something in the TimeInput-NSTextField, my app crashed with a EXC_BAD_ACCESS. I don't see why my app would try to access memory that doesn't exist? Did I do something wrong with the instantation/allocation of my TFDelegate?