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JBrazzell's avatar
JBrazzell
Explorer
Jul 01, 2020

air conditioner / Thermostat problems

Good morning everyone. Should start by saying I'm new to the whole forum thing and new to RVing. So I apologize if I don't have all the information you need, but I will do my best to get you the information if you can help. I recently purchased a 2000 Holiday Rambler Endeavor 36PBD. It has dual dometic ac units on the roof. Size and model number unknown at this time. 5 button wall thermostat displays EE, tried the zone and mode reset, got the FF and then back to EE. Replaced the thermostat (first mistake as I have learned) brand new one does the same thing. Had an old 4 button lying around and it started the front ac unit right up. It seems to work just fine, cools, fan speed adjusts as it should. I however am unable to get the second ac unit to start. I've checked the control board on the rear unit by wiring it into the front units place and it will start and run that ac. The only difference I can see in how they are hooked up is the rear unit does not use the red, black, 2 blue or 2 yellow wires as the front unit does and has a white remote white plug inside the control box. I have 120 volts to both units, just don't know how to get the second unit started. Any help or direction you can provide would be greatly appreciated. Sorry if my questions have already been answered and I just wasted your time. Jim (Newbie)
  • dougrainer's avatar
    dougrainer
    Nomad
    Jul 01, 2020
    1. You cannot use a 4 button where a 5 button is used. The upper control boards cannot communicate correctly. AS you found out.
    2. EE is a COMMUNICATION fault. LACK of communication. This means that Phone type COMM cable is either rusted at the Roof AC connection point(usually this). Or the cable has been cut or damaged. Odds are you have a Penguin Unit(series 65). If so, then rust/corrosion is likely since you have a 20 year old unit. Your model you should be able to access the Control boxes from in side the unit right above the AC ceiling filter plate. You will see the quick connect phone type cables plugged into a splice type connection. Disconnect them and check for rust. The normal sequence on Monaco is to run the COMM cable from the wall tstat to the FRONT AC and then another COMM cable from the front AC to the rear AC. Make sure you check BOTH AC COMM cable connections. Bad connections are either AC will cause wall tstat problems. Doug

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