Dim red light in breaker box..

[bhall5368]

In my Coachman Brookstone 5th wheel I have one fuse that shows a very dim red light. It’s not blown. I know what that means. It goes to my furnace, which is working. I’ve even changed the fuse just in case it was a bad fuse. Anyone ever experienced or seen this? Thanks guys.

[WanderMore]

I’ve seen this in my 2205S but not for the furnace. Mine is related to the circuit for the stove exhaust hood with led light & fan. I contacted WFCO about it and they said it’s normal. In mine, if I pulled the fuse and turned on the hood fan the LED would glow brightly indicating a blown fuse.

[bhall5368]

Maybe I’ll try that with the furnace to see if it does the same. Thanks! I’ve had the camper for about 5 months and it’s been that way. Everything worked so really wasn’t worried that much about it. Just thought I’d post to see if anyone else has seen it before

[D W]

Just a thought here, the blown fuse indicator is a simple device with a resistor and diode paralleled to a fused circuit. It is designed to allow current flow to the LED when the resistance in the circuit (in your case the furnace), is greater than the resistance to the LED (diode). I would inspect the furnace wiring to make sure all connections are secure. You stated that the LED is "dim", so that would indicate a small amount of current is flowing through the resistor to the LED. The resistor might have broken down and lost some of it's impedance.

[bhall5368]

Great advice, thanks! My furnace wiring is actually very easy to get to (hard to believe), I’ll check them out.

[Larry-NC]

Originally Posted by D W

Just a thought here, the blown fuse indicator is a simple device with a resistor and diode paralleled to a fused circuit. It is designed to allow current flow to the LED when the resistance in the circuit (in your case the furnace), is greater than the resistance to the LED (diode). I would inspect the furnace wiring to make sure all connections are secure. You stated that the LED is "dim", so that would indicate a small amount of current is flowing through the resistor to the LED. The resistor might have broken down and lost some of it's impedance.

As you state, the LED and series resistor are in parallel and in series with the circuit loads. The resistor is usually around 330 ohms (orange orange brown). The LED has a 1.5 volt drop when illuminated. See
http://lednique.com/wp/wp-content/up...ll-colours.png , the R (red) curve.

In order to glow, there must be at least 1.5 volts drop in the parallel leg with the fuse, holder clips, and PC board traces and connections. Could you post the voltage at the battery terminals and at the furnace?

And check whether either fuse clip seems loose on the distribution board. It would be easy to damage the connection to the PC board by bending a clip over.

Also wondering if the fuse is plugged so one leg is actually in the clip and the other is alongside the other clip.

It's a cheap move to mount these clips directly to the PC board. There are fuseholders that mount the same way, using the same clips, but with a phenolic (flameproof plastic) support for the clips. Like these or these or these.

[Lloydg]

During my work as an electronics field technician, I came across a glass type mini fuse that had become resistive (about 5 ohms) that was causing all sorts of weird issues. I kept that fuse for some time waiting for my boss to accuse me of insanity, but he never did.

[Grumpy64]

My 2021 Cedar Creek 38EBS does the exact same thing…dim red light on the furnace fuse. Everything works perfectly though.

[bhall5368]

Originally Posted by Grumpy64

My 2021 Cedar Creek 38EBS does the exact same thing…dim red light on the furnace fuse. Everything works perfectly though.

Strange isn’t it..

[bhall5368]

Originally Posted by Larry-NC

As you state, the LED and series resistor are in parallel and in series with the circuit loads. The resistor is usually around 330 ohms (orange orange brown). The LED has a 1.5 volt drop when illuminated. See

http://lednique.com/wp/wp-content/up...ll-colours.png , the R (red) curve.



In order to glow, there must be at least 1.5 volts drop in the parallel leg with the fuse, holder clips, and PC board traces and connections. Could you post the voltage at the battery terminals and at the furnace?



And check whether either fuse clip seems loose on the distribution board. It would be easy to damage the connection to the PC board by bending a clip over.



Also wondering if the fuse is plugged so one leg is actually in the clip and the other is alongside the other clip.



It's a cheap move to mount these clips directly to the PC board. There are fuseholders that mount the same way, using the same clips, but with a phenolic (flameproof plastic) support for the clips. Like these or these or these.

I think I will check to see if the clips are loose

[bhall5368]

Update- so I checked the fuse and where it is inserted. It’s in correctly and made sure it was tight.. nothing loose. Still same. I’ll try to check the volts at the battery and furnace tomorrow. Thanks for the suggestions guys. Also, it’s odd that someone else has the same issue with the same fuse to his furnace.

[chaps2018]

While checking the voltage at the furnace, I would strongly recommend inspecting (do a pull test) on the crimp fittings 1)at the furnace and 2)the wad of wires laying on the floor.

On my Coachmen, I found one crimp connection that easily pulled apart, it was causing intermittent OPEN that prevented my furnace gas valve from opening/firing inconsistently.

[danaswee]

I had the same issue with my 344FL. In fact I think it was the same fuse block. It turned out that one of the sockets where the fuse is inserted was slightly large and wasn't making good contact with the fuse. I used a small needle nose pliers to squeeze the socket, reinstalled the fuse and haven't had a problem since.

[dward51]

It looks to me like the light is for fuse #11 "S/O light" and not the furnace. Or is that just the angle of the photo? I would presume "S/O" is slide out, so are all the slide out lights working?