Troubleshooting E3 Error Code of Furrion RV AC Unit

Published 07/18/2023

Question:

I have installed two new furrion multi zone controllers and a new thermostat and can not get past an E3 error. Dip switches are set per instructions. I have a four wire cable from thermostat to first controller, daisy chained via a four wire cable to the second zone controller. Each controller has a 12 + and -V source from coach. I have switched a/b terminals with no change. E3 I have removed the thermostat to first controller harness, and connected thermostat directly to zone 1 controller. E3 I have then disconnected the harness to second zone and attempted to run. E3 I have reset dip switches to single zone enabled and attempted to drive each unit separately, with thermostat directly connected to harness. E3 I have relocated the thermostat to zone b and repeated the above steps. E3. I can hear a relay close on each controller when they are connected to 12V. Thermostat is non responsive shows temp briefly and the goes to E3 flashing in all cases. Since the furrion instructions devote three pages on how to screw the thermostat base to the wall, and no details on actual wiring instructions other than the two drawings detailing controller internals and cooling unit internals, but no details on field wiring of connections between units I will detail my connections. I have a four wire cable from thermostat to first controller, connected to A zone harness. no connection to analog harness. The four wire harness from a controller is extended to the b controller. It is then tied to the four wire b zone digital harness. Do you have any further troubleshooting ideas? I have a digital DVM, oscilliscope, logic probe and know how to use them.

asked by: Chuck P

Expert Reply:

E3 is a communication error code between the unit and the thermostat. Check to make sure your wires have no kinks or damage and are making a full connection in the thermostat and in the ac unit.

You'll also need to make sure the "A" and "B" wires that make the connection are in the correct ports. Some times in production the "A" and "B" wires can get flipped. If that all checks out it would be time for a warranty claim.

expert reply by: Jameson C