Rooftop AC Cycles on and off and lights at same time

[MATTROBY]

I have a 2004 Cougar by Keystone 31' travel trailer. Recently the rooftop AC has started cycling on and off, before the thermostat should tell it to. It will run for a few minutes, shut off for a few minutes, and then back on, etc, etc. When it does this the main interior lights (controlled by battery i thought) also go on and off with it. It is plugged up at my garage which has the proper circuit that i had an electrician install, and i just installed a new battery. I am trying to get it ready to sell so i can get something smaller but no ac is not a good selling point, lol. ANY thoughts, suggestions, ideas, or help anyone can offer is GREATLY appreciated!! Thanks RV people............

[babun]

I have a 2005 cougar 5'er that had the same AC trouble. It was the thermostat
that was clicking off and on.
The lights were dimming from the AC drawing so much current trying to start so many times, too close together, from shutting off then turning on under a load so many times too quickly.
The start capacitor in the AC was working overtime trying to keep up with the "stat. cycling on and off with just a one or two degree change.
Change the cheapie thermostat out to a better unit.

[beemerphile1]

I suspect your problem is 12vdc related. Double check your battery installation and fuses.

[boosTT]

Do you have a battery connected?

[Golden_HVAC]

Do you have a inverter in the RV?

Do your lights work when not plugged in?

There may be a 12 volt fuse between the battery and 12 volt fuse panel that is bad, if the lights do not work when unplugged.

This is my guess because I think what is happening is the 12 volt output from the converter is powering the lights, and not the battery, so when the converter is overloaded, it will stop producing power, the thermostat has no power to keep the A/C running, and the lights go off at the same time you are losing 12 volt power to the thermostat.

You might also have a shorted wire between the converter and 12 volt panel or the (more likely) 12 volt panel and the battery where it's fuse is located. Or you might have hooked up the new battery backwards, and when the automatic reset circuit breaker is tripped, you have 12 volt power to everything, but when it re-sets, you have no power as the converter is overloaded.

Just a guess there.

Good luck,

Fred.

Also if you have a inverter, shut it off. It might be what is tripping the circuit breaker?

[westend]

The lights dimming indicates a 12V issue. Your converter may have gone South. Check for voltage of at least 13 V+, if connected to shore power. Your A/C thermostat is also powered by the 12V system.