Stuff like this is all about working things out methodically. I do electronic engineering for a living and this is the only way to go about electrics. Start at the sensor, for example change it with a know working one (not a new one cos that could be faulty). Then check the wiring back to the fuse box, do you have continuity from the sensor to the box? Then work from there back to the clock and so on so forth.
Once you have ruled everything out then you should find the problem.
