1997 Sunline T270SR - A/C was modified to always run on high

[scitech1976]

Previous owner modified something in the A/C unit to always run on high when the breaker is on.

Thermostat does nothing for A/C control.
(I also replaced the thermostat, and that made no difference.)

T-stat still works for the furnace.

Anyone have any suggestions on what I can check to see what they did to this unit?

Any suggestions would be appreciated! Just tired of trying to control it with a breaker.

Thanks!

Ryan & Dani

[scitech1976]

We had a power supply failure 2 years ago and had to replace it. I wonder if the 3 amp fuse protecting the 12v control board is blown because of that.

I'll test the fuse and see, and then see what they did to bypass the controller as well.

Perhaps the replacement of the power supply fixed the issue, and I didn't even realize it was the cause.

I'll report back with what I find out.

Ryan & Dani

[scitech1976]

No controls on the unit cover. Just the filter cover.
From peering up into the housing, it appears to be a Duo-therm Model 57915.622

Controller box has the following information on a sticker.
Part #3107541.009
Serial #A014786

T-Stat:
Brand: TycoonWon RV Thermostat 3106995.032

-Ryan & Dani

[opnspaces]

At that age aren't the controls up on the ceiling on the AC itself? If so find the knob that says high, low, fan, and Off and twist it to off.

If not can you take and post a picture of the thermostat? or post the make and model number?

Link to FAQ how to post a picture
Link

[scitech1976]

CA Traveler wrote:
If the A/C cools they perhaps the control board was bypassed for some reason.

Yeah, I think they did bypass something. It cools REALLY well. LoL

Any suggestions on where to start looking for what was done to bypass it?

We are camping at Mohican State park this week and I have the time and tools to fiddle around with it.
I just don't possess the knowledge to know what to look for.

-Ryan and Dani

[CA_Traveler]

If the A/C cools they perhaps the control board was bypassed for some reason.