How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Robert Your Own Question
Robert, RV Mechanic
Category: RV
Satisfied Customers: 13464
Experience:  18 yrs. RV experience including Cummins North West, Country Coach, Monaco Coach - vendor certified.
Type Your RV Question Here...
Robert is online now
A new question is answered every 9 seconds

Furnace not working
, have a suburban sf 35, no power

Customer Question

Customer: furnace not working
JA: Thanks. Can you give me any more details about your issue?
Customer: have a suburban sf 35, no power to either circuit board or time delay, all fuses good. Looking a schematic, there is a valve switch. Where is that?
JA: OK got it. Last thing — JustAnswer charges a fee (generally around $18) to post your type of question to RV Experts (you only pay if satisfied). There are a couple customers ahead of you. Are you willing to wait a bit?
Customer: sure
JA: OK. Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: RV
Expert:  Robert replied 1 year ago.

Hi my name is Robert...

As soon as you turn the thermostat ON and raise the temp you should have voltage going on a wire from the T-stat to the time delay relay and the fan should kick.... One post on the relay should be constant hot, another wire will go to the blower motor and should have voltage on it when when the blue wire from the thermostat has voltage and another wire should be the ground. IF you have no voltage at the relay delay then it sounds like a thermostat issue or the thermostat is not getting power. IF you have power at the time delay you should be able to jump the relay constant hot to the blower wire and the fan should come on. Click HERE and see page 27 for some troubleshooting on this, if you have more questions or concerns please feel free to contact me... Robert

Customer: replied 1 year ago.
Hello Robert,Did you read my troubleshooting issue. I do not have power to either time delay relay or thermostat. I have since manually put 12 VDC to red and blue wire on time relay. Now furnace works, however, I am getting this voltage from refrigerator supply and now blowing that fuse. Specifically, on schematic, power is provide via "valve switch". I am a professional electrical/propane forklift mechanic with own business, I know my way around "components", finding them at this point is my problem.
Customer: replied 1 year ago.
Also, there is a valve directly behind blower with 4 spades, two wires are yellow and two are brown. Is this the "valve" I need to address?
Expert:  Robert replied 1 year ago.


Sounds like you could be talking about the gas valve if the wires are brown and yellow. I DO not think your problem is at the furnace. The signal comes from the thermostat so what is the make and model of the Thermostat can you send me a picture? I think what you are looking at is on some they will have an OFF/ON switch or circuit breaker, I just saw it as well on that diagram it claims it is on the blue wire. The red going into relay should always have power and that should be coming from your breaker panel inside. SO no voltage on the red then I would be looking at your fuse panel for a blown fuse, if you have voltage on the red and not the blue thermostat..... Robert

Customer: replied 1 year ago.
Robert, my fuse panel is fine. When I directly put power to time relay at the red and blue terminal, everything works, including thermostat. I am trying to find source of power for this circuit. There is no circuit breaker and fuses in panel are all good. BTW, when viewing your answer via email, I am "locked" out to reply.
Expert:  Robert replied 1 year ago.

I am not sure why you would be locked at of the reply.

One of your red wires at the delay should always have voltage, that power should come from the fuse panel inside, it feeds the power. So if you were to run a wire from the battery to that post and the furnace starts then it has to be a wiring issue from the fuse panel to the relay.

IF the red is hot but you have no voltage on the blue wire when you turn it ON then it could be the thermostat or wiring for the thermostat, the thermostat is the trigger for the time delay relay. Not sure what else to check on this. IF you want to try another expert please let me know, my goal is for you to be satisfied with my efforts.... Robert

Customer: replied 1 year ago.
bot***** *****ne, schematically I am seeing the voltage in I need, its beyond your expertise for this issue . You have been adequate, but not knowledgeable for my needs. Went to Camper World today and got a professional result.
Expert:  Robert replied 1 year ago.

Sorry.. I try my very best and it is a challenge online. My goal is for you to be satisfied with my efforts, I only get credit when you select a rating. IF you want a refund please let me know, I am fine in whatever you decide. Robert

Customer: replied 1 year ago.
Robert, I see you have high ratings, and will give you an A for effort. When discussing this issue with camper world. I failed to mention this is a 20 year old unit. Thought by giving model you would have known this. Two things, yes I am going to ask for a refund, second, I am going to give you an excellent rating for trying. Fair enough?
Expert:  Robert replied 1 year ago.

I will request a refund for you, no need to select a rating, it is fine. Robert