How recent is the dishwasher?
If it has a mechanical program dial, it sounds like the switch to pump water during the wash cycle has failed. If it is electronic, then it sounds like the main logic board has a fault.
Either way, you need to contact a serviceman.
As mentioned by @Steven. You'll want to get yourself an ammeter, and figure out how much current the appliance is drawing. While shopping for the meter, you'll want to look for a "Peak Hold" feature (though it might go by other names depending on the manufacturer). This feature will allow the meter to retain the highest measured value. That way you don't have to monitor the meter.
Remember when using the meter, you have to clamp it only around one of the circuit wires. If you clamp it around the cord; for example, you'll always get a reading of 0. The best way to do this, is to clamp the meter around the ungrounded (hot) conductor in the panel where it connects to the breaker.
Circuit breakers include overload protection, which is also known as thermal protection. This is typically a bimetallic strip, that pulls the contacts open if it gets too hot. This type of protection is time delayed, since the device has to physically heat up. If the current through the breaker is really high (but less than what trips the magnetic protection), the device will heat up quicker and react more quickly. In your case, however, it's more likely that the current is just high enough to cause the breaker to slowly overheat. This would explain why letting it cool down (waiting), would allow it to run longer once reset.
Your intuition could also be correct, and a loose connection could be exacerbated by the heating due to high current draw.
In either case, an ammeter will be a useful tool to start diagnosing this issue.
NOTES:
- If the breaker is a GFCI breaker, the sanitize cycle could simply be leaking too much current.
- If the breaker is an AFCI breaker, the sanitize cycle may be doing something strange that the AFCI is picking up.
- Thermal protection in circuit breakers can be affected by the ambient temperature, and the temperature inside the panel. So if the panel is in a really hot location, it could trip before it typically would/should.
Update:
Now that it's clear that the circuit is protected by an arc-fault circuit interrupter (AFCI) circuit breaker, I'd like to change my answer. While an ammeter is useful, and testing the max. current draw might be useful. I suspect that the machine is doing something during the sanitize cycle, that the AFCI doesn't like.
Best Answer
If this ribbon flexes , it is possible that it is broken. The LED's work that tells you that you at least have some parts of the cable working. The buttons are usually in a matrix - address and row. or a control signal and simply a row. You would be missing the control line in this case. So I would check the circuit board for a bad solder connection where that cable attaches. Checking continuity of the conductors on that cable - I would be flapping the cable a bit (while testing for continuity) to see if I lose continuity - looking for a cracked cable. Obviously this cable connects to a single touch pad. Simple solution to verify bad touch pad. Trace the wires that need to be connected for any one of these functions (heavy, normal, light, rinse only) then using a jumper wire JUMP them with the wire and see if the function lights up (remember you might need the door switch in the locked position). If it does not try the same for the other non-working buttons and also one of the working buttons just to be sure. None of the functions work except the previously defined working function - then your controller is defective. If the functions all work then your keypad is defective. Remember you are jumping them on that beautiful ribbon cable.