AC fan wont run on auto mode

Thanks for the info I'm going to try to do it today.. Ed

Teeton wrote:
Smkettner, I have a question on ur schematic. I have a dometic ac unit. The question is on the high low fan wires. Do I hook the brown wire direct to the g pin with a switch to open and close the blue wire that's also hooked to the g pin through the switch?? Or do I hook a switch to switch between the brown or blue wires hooked to the g pin?? So the the brown and blue wire are not hooked to the g pin at the same time.. Thanks ED

Both need to be hooked up for high fan. Dometic uses the brown to switch fan on and off, and blue to toggle between high and low. This insures that both cannot be energized at the same time.

Not my picture actually. I generally recommend OEM digital vs the Hunter and Honeywell.

Pic is from this link:

http://www.modmyrv.com/2008/07/14/rv-digital-thermostat

This is my Dometic digital install:
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26820366.cfm

Smkettner, I have a question on ur schematic. I have a dometic ac unit. The question is on the high low fan wires. Do I hook the brown wire direct to the g pin with a switch to open and close the blue wire that's also hooked to the g pin through the switch?? Or do I hook a switch to switch between the brown or blue wires hooked to the g pin?? So the the brown and blue wire are not hooked to the g pin at the same time.. Thanks ED

Success! Looks like it was just a bad connection somewhere. I popped it off and one of those little itty bitty wires was broken. Redid the connection and it's working now!

Yup, that's the guide I used.

Connected like this?

There's no owner's manual for installing it into an RV, but I did follow the instructions from others who have done it before me - with success. I'm really hoping it's not the t-stat itself since I am unlikely to get it replaced with the modifications I have made to it - everything I did was to the plastic housing, but I wouldn't out them past saying I somehow damaged the electronics in the process. It's been installed for less than 2 months, but now that I think of it I think the only way I tested the AC was with the fan switch set manually, so I don't know that it ever worked right.

I'll mess with it some more on my day off tomorrow. I was hoping it was going to be an easy answer saying I did something dumb, but I guess it's not that simple! ;)

It sounds like the thermostat fan switch has failed.
Assuming the hi/lo switch is downstream of the thermostat fan control, and since it works correctly in manual mode, there is nothing wrong with that part of the circuit.

Two thoughts,
> Are you sure you installed the t-stat as per owner's manual?
> If t-stat is installed correctly, you may have a blown fan capacitor.