Old Problem Back Again

[Davidceder]

Earlier this year I had a lengthy post about my 12 Volt, 15 AMP DC fuse blowing whenever I applied DC or AC power to the rig. The interesting thing is it only happened when it was cold. I know, strange! The 15 AMP fuse fed both my living room slide (with the fridge) and my dining room slide so when it blew I lost everything in both slides. Trying to trouble shoot I separated the wiring so each slide was on it own fuse. Well today is was mid 40's and the fuse for the now separated dining room blew. I replaced it a few times but no go. Good news is it isn't the slide with the fridge. As far as I can tell I only loose the three lights in the dining room. If it acts as it has in the past I can replace the fuse when it gets warmer but it will blow when it gets cold overnight. No problems being out a few months this summer. I wanted opinions if I could wire in a resettable circuit breaker so I can troubleshoot this without spending my Social Security on 15 AMP fuses? This is not going to be easy to find. I was thinking of something like this:

https://www.ebay.com/itm/CB41220-Sie...QTM:rk:26:pf:0


If there is something else I might do I would appreciate any input.

[SeaDog]

Something that only happens when it gets cold and then to the slides I would lean toward looking at the type of lube used no the slide rails and gear box. could the lube be stiffing up in the cold and overloading the motor? This is a WAG on my part.

[clr]

Are you trying to bring the slide in or out when the fuse blows? Or does this just seem to happen when it gets cold without trying to move the slides? I would try removing all power from the unit at least the AC and then remove the DC wire from the fuse and use a multimeter to test the wires going to the problem slide. It sounds like you may have a light short to ground in this circuit that is a problem when cold and wire or whatever shrinks or shortens slightly.

[Davidceder]

To answer a couple of questions. This happens AS Soon as I apply either AC or DC. No slide movement involved. Agree it must be a short to ground. As I stated the only thing so far I see that is effect is the three LED lights on two separate switches in the slide. The radio has it's own fuse. I did check the TV amplifier and expected it not to work but it is working, so some 12V is getting into the slide. Don't know which fuse controls the amplifier as of yet and do not think that is really important. I am going to a warmer climate for this week so will look around. I did remember last night that we spent a week at the Grand Canyon a few weeks ago and it was way colder than it is here at home and I had no issues. I will replace the fuse later today and see what happens. Temp forecasted at 82 degrees at the campground.

I still want something to replace the fuse while troubleshooting.

Thanks for the assist

[Flybob]

Interesting problem. Possibly due to expansion and contraction causing a short or a bad component in one of the light modules if they are LED. Be sure to let us know what you find. In the mean time why not try something like this;



https://www.amazon.com/HOUTBY-Circui...ble+blade+fuse

[Davidceder]

Thanks FlyBob, that looks great. I will keep you all posted.

[PSU Turf]

[QUOTE=Flybob;1965018]Interesting problem. Possibly due to expansion and contraction causing a short or a bad component in one of the light modules if they are LED. Be sure to let us know what you find. In the mean time why not try something like this;



I agree with Flybob.

[Davidceder]

PSU Turff, Try something like what? There was nothing there. If you guys think it might be a bad LED light module I might try to take those down and inspect them.

As I thought, I got down to Phoenix, set up camp and put a fuse in and all is well so that leads me believe it is not a bad light. Could a bad light module cause the fuse to blow when it is cold outside?

Temps going down to mid to high fifties tonight so I doubt it will blow. We will see.

Thanks

[Indymule]

I just recently had a intermittent fuse blowing. Found a wire that was wrapped around a bolt under bedroom slide and had rubbed through the insulation. It was a small mark in the wire and movement (from just normal walking) caused the wire to intermittently make contact and blow the fuse. Look for how the wiring is running to those lights, it may be a simple fix like mine but difficult to isolate.

[Tall frog]

Originally Posted by Davidceder

PSU Turff, Try something like what? There was nothing there. If you guys think it might be a bad LED light module I might try to take those down and inspect them.

As I thought, I got down to Phoenix, set up camp and put a fuse in and all is well so that leads me believe it is not a bad light. Could a bad light module cause the fuse to blow when it is cold outside?

Temps going down to mid to high fifties tonight so I doubt it will blow. We will see.

Thanks

do you have tank heaters as part of your pkg? the thermal switch could be bad or weak, some are 12 volt.

[Scrapper]

Try removing each light and disconnecting them from the circuit. It will tell you if it is a light or the wiring. If it is a light then you can figure which it is.


I don't think that the tank heaters will be connected to the same circuit as the slide lights.

[Larry-NC]

Originally Posted by Davidceder

I still want something to replace the fuse while troubleshooting.

Thanks for the assist

Easy! Replace the fuse on the 12v circuit with an incandescent lamp. An 1141 is a good choice. If there's a dead short, the 1141 will light at full brightness and limit the current to the 1.8 amps they draw. As you wiggle wires around near the short, the 1141 will dim or go out.

Here's how to do it:

1. Get a BA15 socket with leads. This one is pretty cheap: https://www.amazon.com/Jili-Online-S...WAP8004GSQQ7CP
2. Get two male spade terminals the same size as the fuse legs. (This assortment will have the right size, but you can get a smaller packet of just the size you need at the local auto parts store. https://www.amazon.com/Swpeet-Connec...381797&sr=1-20
3. Crimp a terminal onto each lead of the socket.
4. Insert an 1141 lamp (incandescent, not LED) into the socket.
5. Plug it in, in place of the fuse.

As noted above, when there's a short the lamp will light at full brightness. As you will wires around and it flickers, you will have found the short.

Larry

[tosh99]

Instead of constantly replacing fuses, fixing the problem is a much better solution than guessing and throwing parts at it. This is where knowing how to use a volt/ohm meter really helps.



Whatever route you take, DIY or hire someone competent, why guess? Also, whatever you do, do not throw a "Johnson" bar fix in place.


It will probably be something like what Indymule went through. It's always something simple.

[Dobbs]

Originally Posted by Larry-NC

Easy! Replace the fuse on the 12v circuit with an incandescent lamp. An 1141 is a good choice. If there's a dead short, the 1141 will light at full brightness and limit the current to the 1.8 amps they draw. As you wiggle wires around near the short, the 1141 will dim or go out.

Here's how to do it:

1. Get a BA15 socket with leads. This one is pretty cheap: https://www.amazon.com/Jili-Online-S...WAP8004GSQQ7CP
2. Get two male spade terminals the same size as the fuse legs. (This assortment will have the right size, but you can get a smaller packet of just the size you need at the local auto parts store. https://www.amazon.com/Swpeet-Connec...381797&sr=1-20
3. Crimp a terminal onto each lead of the socket.
4. Insert an 1141 lamp (incandescent, not LED) into the socket.
5. Plug it in, in place of the fuse.

As noted above, when there's a short the lamp will light at full brightness. As you will wires around and it flickers, you will have found the short.

Larry

What a great idea! I'm going to make one of those just to have in my tool kit.

[Larry-NC]

Originally Posted by tosh99

Instead of constantly replacing fuses, fixing the problem is a much better solution than guessing and throwing parts at it. This is where knowing how to use a volt/ohm meter really helps.

A meter is not always the easiest solution.

And I do know how to use one. I've got a couple of Electrical Engineering degrees and 45 years of industry experience.

In this case, you could remove the fuse and put an ohm meter on the on the load (not hot side). Then station one party at the meter while the other wiggles wires running under the slideout (a likely problem source). Maybe they would see the analog meter twitch or dip. But more commonly these days the meter is digital. Would they see the the digits flicker and return? If they were bored after the first five minutes of nothing?

That's why I suggested the lamp trick. It's easier to detect.

If it isn't a chafed cable, it could be a shorted light fixture or appliance. Once the light bulb is in place, they can disconnect light fixtures and unplug radios, etc. I can't remember whether they were able to make an exhaustive list of items on that fuse. It might be something like an antenna booster hidden in a cabinet.

This is a tricky problem. It only occurs in cold weather. They have to be ready to do something as soon as a fuse blows. And it will take two people.

Larry

[Davidceder]

Larry-NC;

Great idea. Just for clarity. If all is ok your lamp will NOT light until I use something that is on that circuit?? I guess I am asking what happens when the circuit is NOT failing as it did this entire week and the lamp is in place.

So my status is after a week out, we got home Friday I did not experience any further failures, so could not really trouble shoot.

[Larry-NC]

Originally Posted by Davidceder

Larry-NC;

Great idea. Just for clarity. If all is ok your lamp will NOT light until I use something that is on that circuit?? I guess I am asking what happens when the circuit is NOT failing as it did this entire week and the lamp is in place.

So my status is after a week out, we got home Friday I did not experience any further failures, so could not really troubleshoot.

David, that's exactly right. The hardest problems to fix are intermittents, and this is one of them. But cold weather season is coming and that should give you more opportunity (since you said it's a cold weather problem).

Just to test this scheme, you can turn on some loads on the circuit. For example, if you use an 1141 bulb in this test and turn on another 1141 downstream, they should both glow at dull red. Turn on a second one and the lamp in the fuse position should brighten and the other two should dim.

Larry

[Davidceder]

Larry;

I sort of get that. I am not the best at electrical stuff. How would the bulb plugged into the fuse position act if all was normal VS being shorted? The symptom is that as soon as I turn on the battery disconnect switch or apply AC to the rig the fuse blows. So how do I determine a short VS normal situation> Perhaps I am not asking the correct question. It was 38 here this AM so I think I will be able to start diagnosis in the next few weeks. I need to get it in the morning as when the sun warms it up the circuit remains intact. Last winter I went to bed with all working and woke up with the fuse blown. Nothing else was touched during that time. Also at that time the two slides were on the same circuit so when the fuse blew my fridge would not run. I separated the slides and am lucky the problem is in the non fridge slide. Yesterday I did receive my 12V resettable circuit breaker.

[Larry-NC]

Originally Posted by Davidceder

Larry;

I sort of get that. I am not the best at electrical stuff. How would the bulb plugged into the fuse position act if all was normal VS being shorted? The symptom is that as soon as I turn on the battery disconnect switch or apply AC to the rig the fuse blows. So how do I determine a short VS normal situation> Perhaps I am not asking the correct question. It was 38 here this AM so I think I will be able to start diagnosis in the next few weeks. I need to get it in the morning as when the sun warms it up the circuit remains intact. Last winter I went to bed with all working and woke up with the fuse blown. Nothing else was touched during that time. Also at that time the two slides were on the same circuit so when the fuse blew my fridge would not run. I separated the slides and am lucky the problem is in the non fridge slide. Yesterday I did receive my 12V resettable circuit breaker.

Here is a shorter version.
Short circuit: Lamp in fuse position is at full brightness
No short, everything on circuit turned off: Lamp in fuse position is off
No short, other items on circuit turned on: Lamp in fuse position is dim; the more items you turn on, the brighter it will get

Larry

[Davidceder]

Short version works well for me.