300 TD Cruise Control problem
 

The cruise control will set initially and will accelerate and decelerate fine suing the switch handle. It will not turn off by the switch handle nor will it reset from the switch handle. Once the brake is applied disengaging the curise control, the engine must be shut down with the ignition turned off before the cruise can once again be turned on.
Any suggestions on where to start?

Addendum
 

Probably need to add. All was fine untill the switch handle broke off about 3 months ago. I just replaced the switch and ended up with this problem.