Thor AC flashing "E 4"

[tickfarm]

We have a 2014 Thor Siesta and I ran the generator, motor and air conditioning last week for about 15 minutes. Got in it today and when we turned on the air conditioner, the Dometic thermostat was flashing "E 4". The unit came on but we immediately shut it down. Anyone know where to look up this code? Thanks............

[BFlinn181]

You didn't mention what model of Dometic thermostat you have, so some of this may not apply. Download the manual for your model thermostat here.

Various other responses to an E4 error suggests it could be:

Out of range value for outside temperature sensor. Probably only true if you have a heat pump rooftop A/C unit)

Here's a list of Dometic Thermostat codes:


Not sure if this is the same for all models.

To reset:
Press the “+” button and, while holding it, also press and hold
the On/Off Mode button for three seconds. LCD will show
? ? . Press the On/Off Mode button again to turn system off.
This completes the initialization.

Again, not sure if this is for all models of thermostat.

Another suggestion was to pull the fuse for the furnace in the house panel, wait 30 seconds or so, then replace fuse. This is also a 'reset' method.

[tickfarm]

Originally Posted by BFlinn181

You didn't mention what model of Dometic thermostat you have, so some of this may not apply. Download the manual for your model thermostat here.

Various other responses to an E4 error suggests it could be:

Out of range value for outside temperature sensor. Probably only true if you have a heat pump rooftop A/C unit)

Here's a list of Dometic Thermostat codes:


Not sure if this is the same for all models.

To reset:
Press the “+” button and, while holding it, also press and hold
the On/Off Mode button for three seconds. LCD will show
? ? . Press the On/Off Mode button again to turn system off.
This completes the initialization.

Again, not sure if this is for all models of thermostat.

Another suggestion was to pull the fuse for the furnace in the house panel, wait 30 seconds or so, then replace fuse. This is also a 'reset' method.

Thanks Bob. We'll try the above tomorrow morning. Of course, we are trading it for a class A the end of the month. I told the salesman "everything works".

[RDFTravelers]

Originally Posted by tickfarm

We have a 2014 Thor Siesta and I ran the generator, motor and air conditioning last week for about 15 minutes. Got in it today and when we turned on the air conditioner, the Dometic thermostat was flashing "E 4". The unit came on but we immediately shut it down. Anyone know where to look up this code? Thanks............

Had this same issue with one of our units and tried the resets mentioned in the other post but was not successful in removing the error codes. This seems to be pretty common with these units.

Since it is recommended to remove power from the unit I again removed the fuse then removed the inside cover from the vent area and also removed the power molex plug from the control box in this area. After putting it all back together and restoring power error code was gone. This was several months back and have not had any issues since.

Assuming your unit is similar to what we have in the Palazzo, I hope this may help if the normal reset trouble shooting does not workout.

Safe Travels to All.

[tickfarm]

Originally Posted by RDFTravelers

Had this same issue with one of our units and tried the resets mentioned in the other post but was not successful in removing the error codes. This seems to be pretty common with these units.

Since it is recommended to remove power from the unit I again removed the fuse then removed the inside cover from the vent area and also removed the power molex plug from the control box in this area. After putting it all back together and restoring power error code was gone. This was several months back and have not had any issues since.

Assuming your unit is similar to what we have in the Palazzo, I hope this may help if the normal reset trouble shooting does not workout.

Safe Travels to All.

Thanks Robert. I'm trying to avoid CW at all cost.