Jayco RV Owners Forum
 


Reply
 
Thread Tools Display Modes
 
Old 03-29-2015, 09:53 PM   #1
Senior Member
 
newbold1's Avatar
 
Join Date: Dec 2012
Location: Joelton, TN
Posts: 274
AC and Heat Suddenly Stopped Working

I could use some help. My wife and I went camping this weekend and we didn't need to run our AC at all but did run the propane heat just a bit. When it warmed up we ran the AC fan without the compressor when it got stuffy inside. Everything seemed to be just fine.

I got home today from the trip and now suddenly the AC and heat are both completely unresponsive. I have a digital Honeywell thermostat with a toggle switch for Hi/Low fan speed. It's been working for many months without any problem. Nonetheless I pulled the thermostat to check things out and found that I had no 12 volt power coming to the thermostat.

Finding no 12 volt power, I checked all the fuses in the panel box and they are all fine. I have 12 volt power working everywhere else. So, I took the AC air return cover off to trace thermostat wires up to what I believe is the AC controller. I pulled the red wire (identified as Y on the board) and blue wire (identified as B-). I believe that these are the hot and ground terminals. I used a tester and found no voltage coming from those terminals. So, I know its not the wiring to the thermostat but something at the AC itself.

My understanding is that if there is no 12 volt power making it to the thermostat this will stop both the air conditioner and heater from working.

So... what do I do now? Is there a "hidden" fuse on the AC unit itself that I need to check? If so, where is that... from inside the RV or do I go on the roof and remove the shroud up there? Is the problem the AC controller and is that the device I tested? It has the thermostat wires coming out of it and an AC 110 volt wire going into it. Or... is this still too little information with which to determine the likely problem?

I am pretty much stuck unless someone knowledgeable can chime in with some ideas. Otherwise, I guess I will have to call an RV repairman to come out... UGH.

Thanks in advance to anyone that can help me out.

I am attempting to add some pictures to help show what I checked. These photos are up inside the air return of the AC.
Attached Thumbnails
IMG_1836.jpg   IMG_1837.jpg   IMG_1838.jpg   IMG_1839.jpg  
__________________

__________________
Joelton, TN
2013 Ford F350 Lariat Crew Cab 4x4 6.7 Diesel 3.55 Long Bed
2013 Jayco White Hawk 30DSRE
newbold1 is offline   Reply With Quote
Old 03-29-2015, 10:18 PM   #2
Senior Member
 
Join Date: Jan 2014
Location: Aurora CO
Posts: 2,336
Just thinking out loud..... My A/C unit's fan only runs when on 110vA/c. ( regardless if the compressor is engaged or fan only) The blower fan from the furnace is a diffrent system all together, although both are controlled by the same thermostat

the therostate must have some power that it is switchng back to both the furnace and A/c unit , so either a seperare power source or from the furnance ..... I think

I think.....hummmm.....

In line fuse behind thermostat?

You said digital thermostat, so I'm assuming no digital display was working... Meaning either blown or no DC power
__________________

__________________
Jim & Kim from Colorado

2014 Eagle 30.5 RLS
2015 Dodge 3500HD SRW 6.7L
Click on my profile for Mods and notes
Jmooney is offline   Reply With Quote
Old 03-29-2015, 10:19 PM   #3
Senior Member
 
Join Date: Jan 2014
Location: Aurora CO
Posts: 2,336
Pull wires behind thermostat out of wall to see if you have an inline fuse back there
__________________
Jim & Kim from Colorado

2014 Eagle 30.5 RLS
2015 Dodge 3500HD SRW 6.7L
Click on my profile for Mods and notes
Jmooney is offline   Reply With Quote
Old 03-29-2015, 10:25 PM   #4
Senior Member
 
Join Date: Jan 2014
Location: Aurora CO
Posts: 2,336
Diffrent thread today discussed a digital thermostat and talked about fuse mounted directly to circuit board

See this link for photo

https://www.jaycoowners.com/forums/at...1&d=1426783197
__________________
Jim & Kim from Colorado

2014 Eagle 30.5 RLS
2015 Dodge 3500HD SRW 6.7L
Click on my profile for Mods and notes
Jmooney is offline   Reply With Quote
Old 03-29-2015, 10:55 PM   #5
Senior Member
 
newbold1's Avatar
 
Join Date: Dec 2012
Location: Joelton, TN
Posts: 274
I had the RV connected to shore power and both the furnace and A/C are still dead. The thermostat had no fuse on it and there was no inline fuse on the wiring coming out of the wall to the thermostat. I even reconnected the original analog thermostat that the RV came with and that didn't change anything.

On shore power this morning the furnace was running fine. Yesterday the A/C blower fan was running when I needed that instead of heat. Then, I get home and both furnace and A/C refuse to operate at all. Shore power is working as all my outlets, television, microwave, etc. are powered up. DC is working because the 12 volt jack by the control station works and all my lights are working even when I disconnect my shore power.

It seems the issue is isolated to only the A/C and furnace. I sure wish I knew how to fix this. I hate reaching a point and then feeling stuck. I like to solve it myself and learn from it but I guess I might have to get a repairman out here.
__________________
Joelton, TN
2013 Ford F350 Lariat Crew Cab 4x4 6.7 Diesel 3.55 Long Bed
2013 Jayco White Hawk 30DSRE
newbold1 is offline   Reply With Quote
Old 03-29-2015, 11:09 PM   #6
Senior Member
 
newbold1's Avatar
 
Join Date: Dec 2012
Location: Joelton, TN
Posts: 274
Oh... the digital display is dead except when I put batteries into the thermostat. I haven't figured out for sure whether the thermostat should power up without batteries if the 12 volt power was coming in through the wiring. I really don't know as I have always had batteries installed and never really tried it without them to see if the wiring itself would have done the job to power up the digital display.

In any case, even the old analog thermostat fails to work for me now and I know the 12 volt power supply is dead right at the A/C itself before feeding into the thermostat wiring that goes to the thermostat itself.

Now, I am just trying to figure out why there is no power at the source. Bad A/C controller? Hate to sound stupid but is that thing in the photos I took the A/C controller? Those pictures are inside the air return. I took the cover off where you normally clean the filter and this is up inside there. You can see the brownish bundled wire which leads from here through the walls down to the thermostat on the wall.

No 12 volt power here to feed that brown wire which feeds the thermostat. Makes me think A/C controller but just based on reading things about this issue.

What do you all think / know?

I hope I am describing all of this clear enough to help everyone to help me.

Thanks!
__________________
Joelton, TN
2013 Ford F350 Lariat Crew Cab 4x4 6.7 Diesel 3.55 Long Bed
2013 Jayco White Hawk 30DSRE
newbold1 is offline   Reply With Quote
Old 03-30-2015, 12:35 AM   #7
Senior Member
 
newbold1's Avatar
 
Join Date: Dec 2012
Location: Joelton, TN
Posts: 274
I found an excellent photo of the actual part where I tested for 12 volt power. Part # 8330-3851 which is called out as "Junction Box Complete" and on some sites "Control Box". In my earlier photo you see a label numbered 8330B6332 and that apparently is for the entire Flush Mount Ceiling Plenum of which the junction box is one component.

I am a little uneasy to pull that part down but am wondering if there could be a fuse in there or if the only option is that it works or else has to be replaced. In my case, I would assume replaced.
Attached Thumbnails
Control Box - 8330-3851.jpg  
__________________
Joelton, TN
2013 Ford F350 Lariat Crew Cab 4x4 6.7 Diesel 3.55 Long Bed
2013 Jayco White Hawk 30DSRE
newbold1 is offline   Reply With Quote
Old 03-30-2015, 07:59 AM   #8
Senior Member
 
Grumpy's Avatar
 
Join Date: Nov 2011
Location: Where ever the boss says we're going.
Posts: 5,038
Quote:
Originally Posted by newbold1 View Post
I found an excellent photo of the actual part where I tested for 12 volt power. Part # 8330-3851 which is called out as "Junction Box Complete" and on some sites "Control Box". In my earlier photo you see a label numbered 8330B6332 and that apparently is for the entire Flush Mount Ceiling Plenum of which the junction box is one component.

I am a little uneasy to pull that part down but am wondering if there could be a fuse in there or if the only option is that it works or else has to be replaced. In my case, I would assume replaced.
The 12v for the thermostat comes directly from the fuse panel not from the ac unit itself. Either a bad thermostat or a blown fuse. As was mentioned sometimes there is an inline fuse in the wirirng inside the wall. Take the themrostat off the wall and pull the wiring out to check. You won't get 12v at the control box sine it is sent there from the thermostat, not from the control box to the thermostat.
__________________
DISNEY LOVERS
PINNACLE 2015 38FLSA. aka: "Roam Sweet Home"
Grumpy is offline   Reply With Quote
Old 03-30-2015, 08:21 AM   #9
Senior Member
 
tnchuck100's Avatar
 
Join Date: Jun 2012
Location: Sparta, TN
Posts: 1,174
Through reading all of the posts I keep coming back to a blown fuse. Now the question becomes did you check the fuses visually or for actual continuity? It is rare but if these fuse sockets are mounted on a printed circuit board (most are) there could be a bad solder joint there.
__________________
Chuck - Sparta, TN
2012 Jay Flight 22FB, 2 x Honda EU2000i
2013 GMC Yukon XL Denali AWD

EDUCATION is what you get when you read the fine print.....
EXPERIENCE is what you get when you don't.
tnchuck100 is offline   Reply With Quote
Old 03-30-2015, 04:03 PM   #10
Senior Member
 
newbold1's Avatar
 
Join Date: Dec 2012
Location: Joelton, TN
Posts: 274
I finally found it and fixed it. I traced back the furnace hot / ground wires to the furnace and found them dead there at the source. It turns out that all the way on the back side of the furnace there is a switch. It seems to be like a reset trip switch sort of thing. I had no idea what the switch did but figured I would give that a try and cycle it. Voila! The A/C and heat are functioning like normal again. No blown fuses but apparently a tripped safety switch of some sort directly on the furnace itself.

Hopefully, this was just a fluke and the switch didn't trip for some reason that is going to reoccur.

The switch couldn't have been more hidden. It was on the back side of the furnace and I only found it by touching it when actually reaching for wires. Found that switch by accident. Wow!
__________________

__________________
Joelton, TN
2013 Ford F350 Lariat Crew Cab 4x4 6.7 Diesel 3.55 Long Bed
2013 Jayco White Hawk 30DSRE
newbold1 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Virginia State Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -6. The time now is 03:12 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Copyright 2002-2016 Social Knowledge, LLC All Rights Reserved.