Dometic roof top model 630516.321 cools ok wont heat ?

SOURCE: will not shut off

Sounds like a stuck relay on the unit itself. Maybe there is a short in the control wire that comes from the thermostat that activates the fan.

The thermostat probably has one hot wire at all times. The thermostat then chooses which wire to send the voltage down based on your selection. One of those wires is probably for the fan only. Make sure that it is in good condition (no bare, pinched or wires)

SOURCE: dometic ac/heat pump

Would suggest it is drawing excessive current, make sure both fans are going, (inside will cycle low/high), or possible faulty reversing valve solenoid, or could be as simple as loose wire connection, how long does it run for and is it on the same 20amp breaker as the rear?if so start by running only the front unit in cooling 15/20min, check fans running, no unusual bearing noises, switch off for 60 sec then back on heat mode, if unit runs without stopping rewire onto separate circuit, if inside fan not working on heat check bi-metal switch in the airway, if running for a while, fans going but not very warm, check reversing valve.
Note, electrical's should be tested by someone who are qualified in the field.

SOURCE: Older Penguin roof shroud, new style fit?

I just replaced my two 620315.321 shrouds with the newer style without any problems. I went to the Camping World site (and called them) with model no. and they knew what to send me. I also found that they had the best price at $79.00 (member price) with free shipping.

I didnt check your shroud part no.s, but think you will be ok if you do as I did.

If you have any question about installing, you can email me at [email protected]

SOURCE: FAN SHUTS OFF BUT COMPRESSOR KEEPS RUNNING - 6 MONTHS OLD

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.

SOURCE: RV Dometic Duo Therm roof top AC w/heat pump Model

If the Air comeing out is the same as the temp inside the RV make sure the compressor is running and not just the fans. It could be low on freon. If freon is ok then you would need to ck the wiring to the selector switch for a short. It would be obviouse because there will be melted wires. I am leaning toword low on freon since you have already been inside the wiring/control unit.