I broke my AC

Grandpa Hiker · 05-23-2017, 01:41 AM

I have a 2015 FR R-Pod with Dometic air conditioner. Thermostat started giving problems & I replaced it. AC was working fine until someone asked me to document (with text & photos) the steps to replace the thermostat.

After removing the thermostat cover & screws that hold the thermostat to the wall I pulled the thermostat away from the wall & noticed that two of the three wires had nicked places in the insulation.

There was plenty of extra wire inside the wall, so I decided to just cut off the wires & re-strip the outer insulation. This is where I really messed up. Without thinking, I took my cutters & cut the thermostat wire bundle without separating each wire. As I cut the wire I noticed the camper lights slightly flicker.

When I reconnected the thermostat, I got nothing, I used a volt meter to test the negative & positive wires .... no voltage. I assume that when I cut the wires, the cutter blade shorted across the negative & positive wires & has messed up some sort of thermostat control unit in the AC unit.

Is this a problem that I can fix by getting a new thermostat control unit or do I need to go to a RV repair shop?

Thanks for any advice.

PhoneDude 8289 · 05-23-2017, 04:21 AM

Ck the 12V fuse for that circuit. More than likely the short popped a fuse.

Grandpa Hiker · 05-23-2017, 05:02 AM

I could not find a fuse for the thermostat circuit. There is a breaker for the AC unit & a 12v fuse for the furnace, but nothing for the thermostat.

A32Deuce · 05-23-2017, 06:14 AM

Do you have a digital volt meter? You can check if you have power. It would not hurt to check fuses, since you don't know how its wired.

mikel68 · 05-23-2017, 06:43 AM

Might want to check the transformer in the unit. It sends 24volts to the thermostat from the unit. Although it does sound like a breaker is tripped.

OHM out the wires to see if there's a short. Find a wiring diagram of your unit to ensure you know were the transformer is if you got 220/110 going in and no 24/12 volt coming out, that could be your culprit.

Iwannacamp · 05-23-2017, 07:01 AM

I am not familiar with your exact unit, some of the Dometic a/c units have a 3 amp ATC fuse plugged into the a/c control board. It is for low voltage protection.

Grandpa Hiker · 05-23-2017, 09:43 AM

1. Checked voltage on negative & positive thermostat wires = nothing.
2. Checked every fuse & breaker = all good.
3. Took cover off of a/c control board = no fuse.

I am beginning to think that something in the control board box is fried. Think I'll try replacing the control board box.

**Flybob** · 05-23-2017, 09:51 AM

Before you panic, I would spend a little more time tracing the 12V to the thermostat. You shorted the 12V power to the thermostat and it blew a fuse.

**Mr. Dan** · 05-23-2017, 09:56 AM

Quote:

Originally Posted by A32Deuce

Do you have a digital volt meter? You can check if you have power. It would not hurt to check fuses, since you don't know how its wired.

In the original post ======>

Quote:

Originally Posted by Grandpa Hiker

....
I used a volt meter to test the negative & positive wires .... no voltage.

5picker · 05-23-2017, 10:03 AM

Quote:

Originally Posted by Flybob

Before you panic, I would spend a little more time tracing the 12V to the thermostat. You shorted the 12V power to the thermostat and it blew a fuse.

I agree.
Most of these systems get 12v from some supply source to the thermostat and the control in the unit.
The OP will need to find that and likely find a blown fuse.

**Bama Rambler** · 05-23-2017, 11:57 AM

A 2015 model should have the digital thermostat. The connector looks like a phone plug? Is that what you have?

A32Deuce · 05-23-2017, 12:12 PM

Quote:

Originally Posted by Mr. Dan

In the original post ======>

The reason I posted was a lot of the new electronics require the use of a digital meter so that you don't hurt a component.

**Mr. Dan** · 05-23-2017, 12:35 PM

Quote:

Originally Posted by A32Deuce

The reason I posted was a lot of the new electronics require the use of a digital meter so that you don't hurt a component.

Roger that.

Grandpa Hiker · 05-23-2017, 02:40 PM

Mine is a Dometic digital thermostat however it has 3 wires rather than the one that looks like a phone plug.
Dometic 3313189.000 Single Zone LCD Thermostat and Control Kit Polar White Trailer Camper RV

I did use a digital volt meter to check the wires.

I called Forest River Customer Service & they said that the thermostat gets it 12v power from the converter. Rather than maybe making a bad situation worse, I am going to take it to a RV repair shop.

**Flybob** · 05-23-2017, 02:59 PM

Pull each fuse out of the fuse panel and check it.

**Bama Rambler** · 05-23-2017, 04:07 PM

You have the CCC (Comfort Control Center) thermostat. It's the precursor to the current digital model.

As FlyBob eluded to. Actually test the fuses instead of just looking at them. They can look ok, but be blown.

SpringerPop · 05-23-2017, 04:29 PM

Also, be sure that the 12-volt source isn't from the heater (yes, the heater). Though I have an older unit, that's how mine is wired.

If that's a possibility, might you have cut that wire?

Pop

Grandpa Hiker · 05-23-2017, 04:42 PM

I just now pulled each fuse individually & tested it with the continuity tester function of my multi-meter. All tested ok.

Toddupton · 05-23-2017, 04:55 PM

Check the fuse on the furnace I think that has one too

**Bama Rambler** · 05-24-2017, 09:38 AM

If all the fuses test good, then I'd start looking at the connections on the thermostat wiring in and out of the A/C control box. You could have caused a slightly bad connection to burn out.

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