Help troubleshooting RV electrical.

[1963JAM]

I know, I know this is a automotive forum. An EXCELLENT one at that. FBBO has been very helpful with any and all questions on our hobby. FBBO has got a great pool of talent in all facets of this hobby. In fact I was expecting the same from a Forrest River RV forum. Doesn't come close in response or help of any kind chasing an issue on my Sunseeker. I did reach out to FR with some success on schematics and some insight with my issue, but no success.
So I am asking if anyone out there with experience with heat and ac issues on there 2009 Forrest River could contact me would be greatly appreciated.

 

[Richard Davis]

Most RV brands utilize the same manufacturers for the various components. You might try looking in other RV forums for info on your HVAC system.

 

[wahya]

Irv2. And it would probably help if you posted what the problem was.

 

[Triplegreen500]

Agreed. Forest River, Newmar, Winnebago, Keystone, Grand Design - they all buy appliances from appliance manufacturers, they don't make them themselves. Most HVAC is either Dometic, or Coleman. Ditto the power panels - not made in-house (exception being some of the high-end Newmars and Winne's). About the only thing that's "unique" is point-to-point wiring, their structural choices (wood versus aluminum studs; laminated versus aluminum skins; etc), and the floorplans.

 

[72redbird]

What is the issue you are having? I work at an RV dealership, I'll see if I can help.

 

[moparwacko]

I've been working on RV's for more than 30 years (mostly involuntary), but please describe exactly what is happening/ not happening.

 

[1963JAM]

The problem is 2 things that came up after winter storage. One is the AC fan doesn’t work. Second the furnace will turn on without the thermostat on. The furnace will heat up the house to an uncomfortable level. Turning the thermostat on/off does nothing while the furnace is on nor sliding the temp setting slide up/down.
I checked the wiring between the Dometic thermostat and Dometic AC control board and Suburban SF-30 furnace for continuity, to rule out any mice damage. I replaced the thermostat board then the AC control board. Do have wiring schematics from Forrest River.
Since reaching out to FBBO I found a board by the refrigerator (access outside panel) that has terminals labeled A.C. Line, A.C. Neutral, A.C. Heater, Ground. I don’t see this board or terminals on the wiring diagram. Is this refer board sending a signal to the furnace to fire up even though the thermostat is not?
Any and all help is appreciated.
John

 

[1963JAM]

Also in my diagnosing observed that when I disconnect the T1, T2 wires at the AC brain the furnace will not run, but with those wires disconnected and jumped together the furnace will fire up.

 

[bearman]

Did you get a new board that was updated. I have had trouble with that in the new board instructions tell you to move a wire from this post to another. Also have found issues with new boards also. Alot of times have found faults at temp sensors replaced them and good to go.

 

[Triplegreen500]

I'm going to throw out that the "A.C." labels on the fridge board, refer to 110v AC (Alternating Current), not "Air Conditioning". Your fridge should be a 3-way - LP, 12v, 110v. Also, those chips on that board? Look TRASHED. They should not be bubbled like that. Something there has cooked, or is cooking. But if the fridge works...leave it for now.

That said, I can't see how they would affect your furnace unless they share a power supply line for some reason. Possibly power comes from the panel, to the fridge board, then through that via a jumper setup to the furnace. Possibly. Have to see a diagram for that.

Being a class C, I presume you have ducted heat and a/c? Have you physically checked the a/c blower housing to verify no nests or debris is blocking the fan from moving? Have you checked for voltage at the fan motor, to verify if proper signal is being sent from the thermostat?

 

[RemCharger]

I'm going to throw out that the "A.C." labels on the fridge board, refer to 110v AC (Alternating Current), not "Air Conditioning". Your fridge should be a 3-way - LP, 12v, 110v. Also, those chips on that board? Look TRASHED. They should not be bubbled like that. Something there has cooked, or is cooking. But if the fridge works...leave it for now.

That said, I can't see how they would affect your furnace unless they share a power supply line for some reason. Possibly power comes from the panel, to the fridge board, then through that via a jumper setup to the furnace. Possibly. Have to see a diagram for that.

Being a class C, I presume you have ducted heat and a/c? Have you physically checked the a/c blower housing to verify no nests or debris is blocking the fan from moving? Have you checked for voltage at the fan motor, to verify if proper signal is being sent from the thermostat?

Good eye. I've never seen a chip burnt looking like that.
My first thought was flip the board and check for bad solder joints, but probably no point after seeing that.

 

[72redbird]

The furnace control does go through the control board that is located up in the A/C unit. With that being said that control board has gotten hot or shorted like said before. Could be the whole issue. And as someone else said check for a nest up in that A/C unit. Start there.

 

[1963JAM]

Did you get a new board that was updated. I have had trouble with that in the new board instructions tell you to move a wire from this post to another. Also have found issues with new boards also. Alot of times have found faults at temp sensors replaced them and good to go.

Where's the temp sensors, and how do you diagnose a bad sensor?

 

[kiwigtx]

A quick google search throws this up....if it helps any...

Dinosaur 3850712.01 replaces Dometic 3850712013 [385071201-A] :

 

[1963JAM]

I'm going to throw out that the "A.C." labels on the fridge board, refer to 110v AC (Alternating Current), not "Air Conditioning". Your fridge should be a 3-way - LP, 12v, 110v. Also, those chips on that board? Look TRASHED. They should not be bubbled like that. Something there has cooked, or is cooking. But if the fridge works...leave it for now.

That said, I can't see how they would affect your furnace unless they share a power supply line for some reason. Possibly power comes from the panel, to the fridge board, then through that via a jumper setup to the furnace. Possibly. Have to see a diagram for that.

Being a class C, I presume you have ducted heat and a/c? Have you physically checked the a/c blower housing to verify no nests or debris is blocking the fan from moving? Have you checked for voltage at the fan motor, to verify if proper signal is being sent from the thermostat?

I have been in the AC housing. Up top and from inside the house. No nest or debris in fan housing. Have seen bits of foam, that got me metering the wires for grounds or shorts. I haven't checked power to the fan yet.
Fridge and furnace do share power source. Green/ white wire from fuse to furnace than a black/white from furnace bottle cap connector to fridge. Thanks for the heads up on the bubbled component on the IC board.

 

[1963JAM]

The furnace control does go through the control board that is located up in the A/C unit. With that being said that control board has gotten hot or shorted like said before. Could be the whole issue. And as someone else said check for a nest up in that A/C unit. Start there.

I did replace the AC board. Did not fix problem. I disconnected T1 and T2 wires (those 2 wires go down to the furnace) from that AC board and jumped them together clear from the AC board and still had furnace fire up and throw heat in the cabin. AC board is not signaling furnace to fire.
If I drink enough I might see the gremlins f'ing with me.

 

[wahya]

Where's the temp sensors, and how do you diagnose a bad sensor?

Somebody correct me if I'm wrong, but I think this is one. This is in bedroom. There is one in main cabin near a window as well. ( 2 ac's). In my coach.

 

[72redbird]

You are correct, that is one of the sensor's

 

[1963JAM]

72redbird. I see you're in Albequerque. One of my favorite trips 4 years ago rented an RV in Albequerque and drove Route 66 to Grand Canyon and back to Albequerque over 10 days. Finished trip at Enchanted RV park and trading post. Beautiful view of the city lights from up on the hill. Beautiful country you got there in the southwest.

You are correct, that is one of the sensor's