Cruiser HVAC problem

[mark1974]

I have a small swamp cooler on the roof, which works really well and runs cheaply out here in dry Utah. Well this evening I decided to run the A/C for a bit since it was a little humid out. I flipped it on and nothing happened, not even a click from the controller above. Next I kicked the t-stat up to the max of 90 and switched to furnace and again I got nothing. I pulled the t-stat cover off and tested the +7.5 and ground and got nothing. This is the first time I have had any trouble at all. My question is what controls all this and where does the low voltage power come from? I have no idea where to start. The trailer is a 2004 Cruiser 29RK.

[Cobra909]

Hey Mark, I could be wrong, but I believe that you have a 120vac breaker that feeds the A/C unit and any step down voltage would be handled by internal components.

1. Did you verify the 120vac breaker is not tripped?

2. Did you wait at least 5 min. after setting the thermostat to come on. You may have a built in 5 min timer to prevent short cycling of the compressor. ***This should not prevent Heater from coming on...but Heater is 12vdc power (check fuse).

3. Did you try turning the fan switch from Auto to On...does the fan run? If it does, then AC power is good to unit and problem could be one of the controls. (Bad capacitor)



Give us an update once you try some of these please.

Lynn

[mark1974]

Well I just now had a big long thing type up and then decided to go check the 12v fuses once again only more carefully this time and sure enough I had one that was blown. It is labeled Aux. so I guess this runs the HVAC system. Wonder why it blew, hopefully it was just a fluke or weak fuse. Anyway things run now and we shall see what happens.

I had already checked the breaker and all the other switches with nothing happening. I hadn't tried waiting 5 min. because mine doesn't have a delay, at least not at first start up.

You are right that there is an AC 20A main breaker but the control box in the ceiling will still click even if the main breaker is off (found this out about a year ago when the main kicked off while I was away and all I got was a click when I tried to turn the A/C back on) so this indicates two separate systems. At least I know where it gets its 12v+ power now.

Thanks for the reply

Mark

[dalemac377]

It seems like there was a thread awhile ago that mentioned that there was also a 5 (?) amp fuse inside the A/C unit that supplied power to the thermostat. I believe you had to remove the A/C ceiling cover to find it

[mark1974]

Thanks, that's good to know for future reference.

[Cobra909]

Well, there you go...learned something myself.