Originally Posted by jdmedhurst
No power on shore power to outlets, only while generator is on.
Ok, you only have power to your 120 volt outlets when you're on generator power.
First thing I'd do is check to see if you have 120 volts on the shore power "input" terminal of the transfer switch when connected to shore power. If you do, the transfer switch is probably bad. It should automatically transfer this power to the output when it senses shore power. We can assume the connections on the output of the transfer switch are good since you said you get power to your 120 volt outlets when you're on generator power.
If you do not
have 120 volts at the shore power input terminal of the transfer switch when connected to shore power, then you've got a bad connection somewhere between the shore power source itself (RV park pedestal) and the transfer switch. Problem could be as simple as a bad outside shore power cable, or bad connection somewhere between the trailer's outside wall shore power connector and the transfer switch.
Safety first. If you're not comfortable making these voltage checks, highly suggest contacting a qualified electrician or a local RV repair facility.