Hello
OK, unfortunately when you have an portion of the control circuit is not responding, the problem is almost always a short on the circuit itself.
the only way of resolving this problem, is to replace the circuit with a new one. If the unit is still in the warranty period, take it back to point of purchase and get the unit replaced, rather than repaired.
You will also be able to order a new replacement part, and attempt to install it yourself, however i will not suggest you try it if you ave not done it before.
You will be able to order the part needed
HERE.
Please fell free if you need any further assistance.
Kind regards
Andrea