99 SunnyBrook , no furnace, weird stuff with A/C

[slachammer]

First I got this old 99 SunnyBrook, no history known.
I got A/C working, had a broken wire , but when I turn A/C to off position , thermostat will click intermittently , Had A/C running last night , turned it off this morning and the compressor still runs in the off position , freezing evaporator core. I had to unplug the A/C harness from control box (circuit board box) , or shut off main breaker.

Now I tried to get the furnace running , and found that there is no power at the blue wire connected to the time delay relay. I jump a hot wire to the terminal and furnace motor starts spinning after a few seconds, then stops. I put a new thermostat in the trailer , I traced the thermostat furnace wire (white wire) to A/C unit, has 12 volts , it goes into the control box and no voltage comes back out (blue/white wire), which I'm pretty sure is the wire running back down to furnace.

are the control boxes known for any of these issues, should I order one and put it in.
Any other ideas of what to check?


parts in my trailer
duo therm
model 57915.622 13500 btu
circuit board 3107168.001
atwood furnace 8531-iv-dclp


Anyone know of a good circuit board or control box assembly that would fit this model? I google it and the numbers are all over the place, which ones are compatible

[MrMark52]

It sure sounds to me like you’ve got a wiring error at the thermostat.

Combined AC/Heat stats normally allow for 4 wires - a hot, wire which switches thru the stat to tell the gas valve to open, or tell the compressor to run, and to tell the fan to run.

The compressor can run independently of the fan and is controlled separately from the fan.

The fan will run continuous when the Fan-On/Auto switch is in On.
The fan cycles with the compressor when the Fan switch is on Auto.
When heat is called for, power is fed to a control board for the furnace that tells the fan to run for about 30 seconds, then it tells the gas valve to open.

It sounds like you have the stat wire for the fan and compressor reversed, and the Fan switch on the stat set to On. And then when you tried the heat, the Auto/On switch was moved to Auto. Although this scenario would require a change to the temperature setting on the stat, as well as the actual coach temperature.

[slachammer]

the wiring looked original , I took a picture and put it the same way with new thermostat,
power goes from thermostat to a/c unit in ceiling power foes in but does not come back out , I'm gonna try an a/c circuit board

[slachammer]

would anyone have a wiring diagram of the thermostat connections
I have a 6 wire set up

[slachammer]

when I get back up to the mountains, I'm gonna double check set up

[slachammer]

so I put a new circuit board up in the A/C unit. (fixed the A/C issue , compressor wouldn't shut off with thermostat)
still having furnace issues
12 volts goes from thermostat up to A/c circuit board, power goes in but does not come back out. (blue wires)
I tried two different circuit boards plus the original.
If I jump the wires in the ceiling I can get operation of the furnace.

what else can tell power not to come back out of the A/C circuit board box?