Go Back   Montana Owners Club - Keystone Montana 5th Wheel Forum > MOC on M.A.R.S. > Repairs & Service
Click Here to Login

Reply
 
Thread Tools Display Modes
 
Old 11-06-2019, 01:31 PM   #1
usaf_retired
New Member
 
Join Date: Mar 2017
Location: Solomon
Posts: 9
M.O.C. #19507
2017 3791RD furnace issue

Been troubleshooting furnace issue. Furnace works ok when jumping the 2 blue thermostat wires back towards the furnace. when I wire it back to normal i'm having a 12 volt power issue. It sometime has a delayed start after requesting heat. Blower will start up for about 2-3 seconds then shuts back down. blower might try to start up again, then does the same thing...shuts back off after 2-3 seconds. It's like it's not getting a steady 12 volts. I went on top the RV (rear unit) to check wiring up there. I cleaned the furnace connection to the ac control board...no help. I put a new Dinosaur control board already. called Dinosaur tech line. He says there is corrosion somewhere causing it. Anybody have a idea what the trouble could be? Thanks
__________________
Darrell & Judy
2017 3791RD
2017 Ford F350 DRW 4WD
usaf_retired is offline   Reply With Quote
Old 11-06-2019, 02:38 PM   #2
ChuckS
Montana Fan
 
Join Date: Dec 2017
Location: Mountain Home
Posts: 220
M.O.C. #20949
If this is a CCC2 Dometic thermostat the thermostat receives 12 volts from the air conditioner electronic control module up on the roof... the wire is a 4 conductor RJ45 connection on back of thermostat and up at control module

Id try reseating connections at CCC2 and up top on roof... the other two wires in that 4 wire line are for the CANBUS data telling control module what to do..

You stated you checked the two blue wires up top that go to furnace..did you check the joining connections on those two wires at back side of furnace where the connect to wires running up to roof unit
ChuckS is offline   Reply With Quote
Old 11-06-2019, 05:04 PM   #3
Daryles
Montana Fan
 
Daryles's Avatar
 
Join Date: May 2019
Location: Alton
Posts: 286
M.O.C. #24086
Some people have had to change the sail switch, some have changed the black self resetable fuse in the fuse panel with a regular fuse (just for troubleshooting).
There is a furnace TS pdf in the files folder. Hope it helps.
http://www.montanaowners.com/forums/...hp?do=cat&id=3
__________________
Daryl
Daryles is offline   Reply With Quote
Old 11-06-2019, 06:43 PM   #4
usaf_retired
New Member
 
Join Date: Mar 2017
Location: Solomon
Posts: 9
M.O.C. #19507
Quote:
Originally Posted by ChuckS View Post
If this is a CCC2 Dometic thermostat the thermostat receives 12 volts from the air conditioner electronic control module up on the roof... the wire is a 4 conductor RJ45 connection on back of thermostat and up at control module

Id try reseating connections at CCC2 and up top on roof... the other two wires in that 4 wire line are for the CANBUS data telling control module what to do..

You stated you checked the two blue wires up top that go to furnace..did you check the joining connections on those two wires at back side of furnace where the connect to wires running up to roof unit


Thanks for your info. I did get it back up and running normal. I did redo the connections at the thermostat (swapped it with the bedroom stat) before I posted here. I pulled the 2 furnace spade connectors at the ac board up top and cleaned the posts. You mentioned the RJ45 connector up top. I didn't see that. Where is it located? The thermostat blue wires behind the furnace to where it's tied into the rv wiring connections were poorly crimped. i can see bare cooper. I can't reach that far in there to properly correct it. I don't what to pull the heater out at this time. Cold weather coming. I reached back there with a probe i have to separate the wires best I could so they don't touch.
__________________
Darrell & Judy
2017 3791RD
2017 Ford F350 DRW 4WD
usaf_retired is offline   Reply With Quote
Old 11-06-2019, 06:50 PM   #5
usaf_retired
New Member
 
Join Date: Mar 2017
Location: Solomon
Posts: 9
M.O.C. #19507
Quote:
Originally Posted by Daryles View Post
Some people have had to change the sail switch, some have changed the black self resetable fuse in the fuse panel with a regular fuse (just for troubleshooting).
There is a furnace TS pdf in the files folder. Hope it helps.
http://www.montanaowners.com/forums/...hp?do=cat&id=3
I already put a new sail switch. I did pull that black resettable fuse and replaced it with a regular one. Matter fact I ended up breaking the black one while pulling it out. Does it have to have a resettable one? Thanks for your info.
Oh yeah I did get the furnace running again.
__________________
Darrell & Judy
2017 3791RD
2017 Ford F350 DRW 4WD
usaf_retired 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
Forum Jump

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by Montana RV, Keystone RV Company or any of its affiliates. This is an independent, unofficial site.


All times are GMT -6. The time now is 06:34 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
×