Dometic a/c compressor shutting off - Dometic Heating & Cooling

Most likely the compressor is controlled by a relay. The relay can become stuck on and would need to be replaced. I would try removing the power source before spending any more money.

This is very much relay problem. The olden days relay get stuck due to residual magnetism. Or spring would have snapped. Or contacts would have bonded permanently. Check these or replace the relay totally.

Replace the contactor on top of the compressor. It is not telling the compressor to shut down

check the thermastat

Depending upon the model of your air conditioner, this may be normal operation.

My newer Dometic air conditioner will run the compressor in a "reverse" mode without the fan occasionally in order to heat the coils. This is done to defrost the coils. After the frost is gone, the fan switches back on and everything goes back to normal.

check the thermostat switch it might be stuck. or over setting.

It could be a relay for the compressor is sticking in the run position.
If it is only about one week old take it back to the dealer for service or call them and tell them your problem. This should be covered by warranty and the dealer can refer you to someone authorized to do the work.