Furnace and reading lights out? 1977 Argosy 20 MH

[ViewRVs]

Due to the cold nights, I need to get my furnace working! The reading lights over the dinette are also out.

I have found the 12v fuse panel under the dinette and checked every fuse. I replaced some of them and tested all of them with my volt-meter on both sides of the fuses.

The previous owner indicated that this situation is a fuse located in that spot. I cannot for the life of me figure out why the furnace or lights are not working!

I also checked the fuse on the furnace and it looks fine. I have an old wall thermostat but you do hear it engage as you turn the dial up. The furnace makes NO noise whatsoever. No fan, no igniter, nothing!

Is there something I am missing?

[idroba]

First, check that you actually have 12 volts, and ground at the furnace wires. They will be the ones that are not blue, coming out of the furnace (may be yellow and white, or red and yellow or red and white, not sure). If you don't have power there, you will need to trace back to find why. Maybe run a temporary 12 volt line to the furnace if you can't find the problem. If you have 12 volts, and are sure of the quality of the ground line, next jumper the thermostat wires together, either at the furnace or the thermostat. You should then get some action. Some of the old thermostats just get tired and don't work.

I assume you have an original pilot light furnace. If it does not work after checking those things, let us know. But any 35 year old furnace is a candidate for replacement.

[ViewRVs]

I spent about 6 hours trying to diagnosis this problem.

First, my 12v outlet near the sink (with the TV antenna) is also not working. I unscrewed it and tested the wires. zero volts. zero when using another ground.

Due to the location of the old Sol-Aire furnace, I could not get back to the electrical connection. The electrical connection is on the left side against the interior wall. There is no easy way to get to it without major de-construction. I checked for 12v at the thermostat and it read zero. I even tried connecting the wires to bypass the thermostat and that did not work. The 12v outlet also read zero (even when using another ground (screw in wall).

Strangely, the lights over the dinette read .7v to another ground (screw on wall). I pulled down the light fixture hoping to find a loose wire.

I tried to isolate the circuit for the reading lights by pulling fuses. When I remove the SPE4 fuse, it drops to .1v. This circuit is labeled as the 'Power-on-light (Control Panel)'. I was hoping one of the circuits would drop it to zero! It is really odd that the voltage drops to .1v but not zero. That implies that some power is coming from somewhere else.

I have replaced all of the house panel fuses with new fuses. I tested both side of the fuses with my volt meter.

Bottom Line: I could not isolate the circuit. I did not find any loose connections. I am pretty much at the end of my rope on this one. It might be time to seek a professional. The other option is to just rip out the Sol-Aire furnace! That sounds exciting but does not solve my electrical issue in the light over the dinette.

The only good thing is that I am no longer getting the Polarity Warning Light on the outside corner. The only thing I did was to remove an old 110v outlet from the inside. The outlet had some damage of some kind (overheated wire?). I pulled it off and taped off the ends with electrical tape until I can get the outlet replaced.

[TG Twinkie]

Did you check the output of the converter?
Did you check the voltage at the house battery.
Can you post some pics?
Do you have a battery charger?
If you have a battery charger, disconnect the converter, leave the battery connected, then connect the charger to the battery and see what happens.

[ViewRVs]

Did you check the output of the converter?

Not sure how. The Univolt wires go behind the 12v panel.

Did you check the voltage at the house battery.

The house battery is at 13.08 volts.

Can you post some pics?

Yes. I have attached pictures of my panel, Univolt, and the old furnace.

Do you have a battery charger? If you have a battery charger, disconnect the converter, leave the battery connected, then connect the charger to the battery and see what happens.

I did have the house battery connected to a separate charger. I don't have issues with the other 12v items (lights, radio, water pump, fan).

The main issue is the inoperable furnace, no voltage at the thermostat and 12v outlet, and the reading lights with little voltage where I cannot isolate the circuit.

[TG Twinkie]

Ok! Check for voltage between the large red wire on the left labeled trailer battery and the large white wire on the right hand end of the shunt (the brass bar at the center bottom)
If you have voltage, then check for voltage on the right hand end of each of the fuses on the right side of the fuse panel.

[TG Twinkie]

When checking for voltage at the fuses. The black lead of your meter should be on the white wire at the shunt. The red lead will be used to check the right side of each fuse.

[ViewRVs]

1) I removed the house battery and I still have 12 volts at the fuses. It appears the Univolt is working.
2) I checked between the large red wire and white wire at the shunt, 12 volts
3) I checked between the black lead on the white wire and the fuses and I have 12 volts all around.

Here is where it gets interesting.

4) I tested the 12v outlet on the wall with the continuity tester. The neutral/ground side tested OK with the light in the ceiling. The positive side did not work when checked with the center light. It appears the purple positive wire has no juice!

I also have two extraneous wires near the 12v distribution panel, a white wire and a brown wire. Neither one have continuity to ground. I have continuity for both on the positive side.

5) The white wire causes a loud CLUNK in that large silver thing (sorry I don't know the name) on the left.

6) The brown wire causes the dash lights to come on and this after-market "Light Reminder" alert box to start beeping (even though the lights are off on the dash). Someone must have added this little "feature". FYI - The dash lights work fine using the pull switch on the dash. The Light Reminder is disconnected since it does not currently go off if I pull the light lever with the keys out.

I have a message in to Airstream to see if they have the coach wiring diagram for this unit. I have the chassis wiring already.

[TG Twinkie]

The large silver thing that goes "clunk" is a solenoid. It switches the DC voltage. Can't tell you what it switches, but I would suspect the starter battery. If you pull the large fuse on the upper left corner of the fuse panel. Do you still have 12 volts between the + buss (the metal plate between all of the fuses) and the white wire? This should be the charge line from the alternator in the MH.
With both the fuses on the left side pulled do you still have 12 volts?
What do you read on the pink and yellow wires that go to the fuse panel?

[TG Twinkie]

Meant to say it looks like a PO has been doing some imagineering. With the dash lights etc.
What color are the wires at the thermostat?
I notice the furnace has red, yellow and black wires. A pair of these should be the power to the furnace. If the yellow wire at the fuse panel does not have 12 volts, this could be the problem.

[Alumaholic]

Univolts fail incrementally, not catastrophically.
They just fade away through the years.
I lived with a failing univolt for 3 years and about 9,000 miles of Airstreaming in my first Airstream. Like a physician with a stethoscope and a blood-pressure cuff, I was always under the counter with my multimeter checking the Univolt, and in the battery compartment with a battery tester.
Sadly, it never really failed completely, though now I wish it had.
When I finally installed a new converter with a charge wizard, I was amazed and delighted at how it simplified my life.
When I got my second Airstream, I replaced the Univolt immediately.
There is simply no reason to waste time trouble-shooting a 12volt electrical systems that includes a Univolt.

[pgr32e]

Another thing to try is to make sure all the wire connections on the fuse panel are working. I had one that had a screw stripped and power was intermittent even though the fuse tested fine. The only way to cure it was to solder the wire into the fuse holder or replace it. Works fine now.....Phil

[ViewRVs]

With both the fuses on the left side pulled do you still have 12 volts?

When I pull both fuses on the left, I still have 12 volts.

What do you read on the pink and yellow wires that go to the fuse panel?

I have 12 volts on both wires.

What color are the wires at the thermostat? I notice the furnace has red, yellow and black wires. A pair of these should be the power to the furnace. If the yellow wire at the fuse panel does not have 12 volts, this could be the problem.

I have a white, purple, and two blue/white wires into the furnace. The two blue/white wires go to the thermostat. I was not able to check voltage due to the location of the wires. I do not have any voltage at the thermostat. I also tried connecting the wires to no avail.

Another thing to try is to make sure all the wire connections on the fuse panel are working.

I checked this. The connection seems to be good I swapped wires and the problem followed the purple wire.

Wrap Up:
Since all three items (light, 12v outlet, and furnace) that do not work all have the purple wire in common, I am guessing the issue is with the purple circuit. Everything else is working fine.

I also determined that one extra red wire went to an old Propane sniffer that no longer works. I disconnected that wire and will remove the unit (and replace it) soon.

[TG Twinkie]

Sounds like you have tracked it down to the purple wire. I would check the device closest to the converter first. That is, of the devices that don't work.
But before you do that, if you can remove the purple wire from the fuse panel and connect it to a known 12 volt source. Just to be certain you don't have a bad connection causing a voltage drop.
With both the fuses on the left removed, you still have 12 volts, that says the converter is working.
As for the thermostat. If you are trying to read voltage between the wires you won't get a reading since it is in effect a switch leg. And without power to the furnace you wouldn't see anything.

[ViewRVs]

The good news is that the furnace works! The bad news is that the wire from the overhead light to the panel is bad.

I used the Ohm function on my multimeter to check the wires. I had connection from the light to the 12v outlet on the other side of the coach.

I also bought a 15ft section of wire for testing. I was able to run the furnace from both the 12v outlet and the light wire. My issue is clearly between the light fixture and the 12v panel.

The purple wire goes onto the ceiling. How in the heck am I supposed to replace a wire that goes into the ceiling and comes out below the dinette?

Oh, please ignore those curtains. JPA Drapes is making a new set while you read this!

[dadstoy]

Originally Posted by 1985air345

The good news is that the furnace works! The bad news is that the wire from the overhead light to the panel is bad.

I used the Ohm function on my multimeter to check the wires. I had connection from the light to the 12v outlet on the other side of the coach.

I also bought a 15ft section of wire for testing. I was able to run the furnace from both the 12v outlet and the light wire. My issue is clearly between the light fixture and the 12v panel.

The purple wire goes onto the ceiling. How in the heck am I supposed to replace a wire that goes into the ceiling and comes out below the dinette?

Oh, please ignore those curtains. JPA Drapes is making a new set while you read this!

I had JPA Drapes make me a new set for my 280 a couple yrs ago. They are beautiful and I'm extremely happy with them!

[ViewRVs]

Don't get sidetracked by the curtains! . Do I have to start pulling panels to follow that wire and/ or rewire? My hunch is that a connection is loose in the wall.

I'm pretty sure the answer is yes but I guess I need confirmation!

[TG Twinkie]

Where did the purple wire that is hanging down from the light fixture connect? I see it has a spade lug.
Also , in the first pic it looks like there is damage to the purple wire about 6" back from the spade lug. Looks like it was pinched or something. Is it the same purple wire in both pics?
I only see 1 purple wire in each picture. Are they the same wire? Can't see the spade lug in the second picture clear enough to tell if it is male or female. The first pic shows it clearly being female.
I would expect to see a second wire. Are you sure it hasn't just become disconnected from the wire that goes to the fuse panel.

[ViewRVs]

The damage to the wire is from the splice that goes to the other reading light. I did check the power from that spot also. The female end plugs into the male part of the switch.

There is a lavender wire and a darker purple wire. It is the darker one that is in question.

[TG Twinkie]

I am confused. Which is easy to do.
I only see 1 purple wire hanging out of the hole where the light goes. You mentioned that when you connect power to that wire you have power to the furnace. Is that correct?
Is the wire at the fuse box purple or lavender? I don't see a lavender wire.
What are the two switches for?
The wires look in good shape. In looking at the fuse panel it appears that the purple wire goes into a sheathed cable along with other wires. Is this correct. Where is the furnace located relative to the light. Are you sure the purple wire doesn't go to the furnace first then to the outlet and light. When you connect the power to the purple wire at the light you could be feeding back to the furnace and outlet.