1. Most CCC systems the CCC IS the Zone 1 temp sensor and the Zone 2 has a remote eye on a wall in the Zone 2 area
2. It is RARE for a CCC2 to malfunction
3. The most common cause is a corroded end on the Phone type communication cable connections.
4. IF you have Penguin model Roof AC units, the odds of corroded communication cable ends increases dramatically, especially after 3 years of operation.
5. You have these cables at both AC upper control boards and then the one on the wall ccc2 tstat. The corrosion will be very evident.
6. So, unless you want to pay and throw parts at it, you need a qualified RV Tech to check your system. Doug