Same old electrical issues, better but not fixed

Our 33RK has been in the shop 2 1/2 months out of the last 3. Most issues have been resolved, but we still have electrical problems.

We still have a problem when the slides are closed and we are pulling the unit. We turn on the propane and fridge and the slide fuse blows.

The shop traced wires and tightened where they could. Re-wired a few things and checked amp readings. It got to the point that when all three slide wires were connected to the panel it was still blowing the fuse, but not when each slide was connected individualally. They finally got to the point where it wasn't blowing so I picked it up for the fourth time.

I pulled it 30 miles and when I parked it the 30 amp fuse at the battery and the 15 amp slide fuse had blown.

I trickle charged the battery and reconnected it. The fuses did not blow right away with slides open or closed.

We decided to take on a trip to test things out a little more. We turned fridge on propane and started to drive. I checked it several times on the way and the fuses were fine. But four hours later the 15 amp fuse blew again.

It seems to happen more frequently when the battery is low. When there is a low battery I would think things would just not work and not be able to blow a fuse. Can low battery be an issue?

We checked loose connections and looked for wires being pinched as they enter the slide (as others have mentioned) but could not find any issues. Many connections have been tightened and this may have helped because the frequency of blowing fuses has lessened, but it still is not resolved.

Can the fridge circuits or other electronic issues be causing all these issues or does it have to be related the the slides?

The converter was replaced and not sure what to check next. Going nuts, so please help if you can.


Sent from my cell phone. Please forgive typos and spelling errors.

Hi Duane,

I'm confused by some of your post. What slide fuse are you talking about? I don't know all the different models and how they're wired, but I thought slides are powered from 12V buss bar circuit breakers near the battery. Sounds like you're describing a glass fuse in the fuse panel which I don't think would be a slide fuse.

I might be wrong, and it might be a fuse in the fuse panel, that supports the slides. But I'm confused. Can you clarify?

Have you traced the 12V wires that power the refrigerator to make sure they're not pinched, and if they go through junction boxes, that the connections there are ok?

I will try to send a pic. The 15 amp.fuse is at the bottom of the panel. Little blue one fifth from right and labeled slide.

I do think it is 12v, but still learning this stuff. I traced the wire as far as I can and don't see any pinch, but can't follow wire all the way.

I think it is a pinch or short but can find it.

When the fuse blows it shuts off all electric items to the slides, but the slides still move in and out, so maybe it should be labeled different.

In post #3 I meant can't find it. Can't edit it on phone.

Sent from my cell phone. Please forgive typos and spelling errors.

If you're talking about the one next to MAIN, that looks like a circuit breaker which would be for 110v outlets located in the slide. When it trips, do you just have to flip it back on? Fuses have to be replaced when they blow.


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Yeah. It's the one that needs to be replaced.

When the fuse blows, I assume the fridge stops. What else stops working?


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All of the lights to the slides stop working along with the fridge.

You might try looking for a junction box under the slide to see if the 12v wiring goes thru. I think there was a similar problem detailed recently where the wires were shorting at the box.


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Have you tried traveling with the refer turned off? You might be looking for a problem there, when the refer is not the issue.
You said that after 4 hours of traveling the fuse blew and that happened more frequently when the battery is low.
So my next question is, was the battery charged after traveling?
It just sounds like there is a short somewhere. You just have to dig a little deeper.
There should be a metal junction box below the slide and attached to the frame. Check the wires in there as well as pulling the belly material down in that area and check those wires.

Peace
Dave

We caught where a screw holding a junction box to the frame had sheared off, causing the box to shift and wires to rub where they go through the frame into the underbelly. No damage, but could see rub marks on the wire housing. Could not see the wire rubs from the outside, only after dropping underbelly.


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I will keep digging. I noticed the junction box at the king pin is loose. Not sure if it should be. Last two days it was dark when.we got back to the trailer. I should have some time to dig tomorrow. I will also try to pull it without fridge on.

Duane,
Electrical troubleshooting requires a systematic approach, understanding exactly what and when things happen. Fuses blow primarily because of a short to ground. A low battery (B+) will not effect blown fuses. Low B+ means less current available therefore less chance of blowing fuses. However your B+ can supply 150-200 amps of current and your circuits are fused well below that.

In one of your earlier posts you said that when the three slides were not connected no blown fuses. So when which slide was connected did a fuse blow???? What you seem to have is an intermittent short to ground being caused by the movement of the slide, if I understand you correctly. Checking for loose connections is not likely the problem. A loose connection will give you a temporary or intermittent open (no power) not usually a short which would then blow a fuse. It is possible that a loose nut could allow a wire to move over and touch a ground but that is highly unlikely. Here's a way of searching for the problem. you have to isolate the circuit that is giving you the problem You can isolate the circuit by either removing fuses or disconnecting wiring harness plugs. First remove fuses and make sure you know exactly what is powered by that fuse. Label the circuits in a separate notebook so you have room to write all that the fuse controls. I don't know how you are disconnecting the slides. If you are removing fuses that's OK. If you are unplugging wiring harnesses that's OK also. Disconnect all circuits that are involved. Drive the unit to get it shaking and moving around. Now plug one circuit in and repeat the movement. If the fuse does not blow when you connect the first slide then that slide and circuit are not the problem. If the fuse blows then that is where you start to look.

Also, A loose ground will not cause fuses to blow. A loose ground or chassis case screw that is loose will simply not allow a path for return current and a circuit just won't work. No ground return path and nothing happens. Only a shorter path to ground bypassing a load causes excessive current and a blown fuse. I've seen how sloppy many units are wired. It's my guess you've got a hot wire that is rubbing intermittently on a chassis ground causing the blown fuse. Isolate the circuit then start your search. If you can isolate the circuit by removing a fuse then try disconnecting a wiring connector to further remove things from that circuit. If you can disconnect half way down the circuit and the fuse still blows then it was before the connection. If it does not blow then it is in the section you just unhooked. Sorry for the long post but it takes a lot of explaining sometimes.

TeJay

Reading this thread is confusing to me. All the way it talks about fuses but in reality it is the circuit breakers that are tripping, I think. A circuit breaker is not a fuse but acts like one. The first thing I would check is the connections to the circuit breakers and the bus bar in the breaker panel. Then I would check the junction box under the slide to be certain all the wires are tight. Be sure the circuit breakers are properly labeled as it is not uncommon to have them mislabeled.

DuaneG, I agree with TJay, An intermittent short (B+) to ground are tough to find. Use to have a "short finder" and I bet TJay had one also. You connected it in the the fuse holder and started yanking..tugging on wires. It would buzz loudly when the short was present. Quite frankly I dont know if they still make them. But it was a god sent to auto techs. Right TJay

There has to be a B+ wire touching the frame or something metal that is grounded to the frame. Check behind any cabinets in the suspect slides to make there is not a junction in them also. Your problem could be there. It could be the lites not the fridge.

Cranky you are correct again. This has to be a B+ short to ground caused by movement of the slides. As far as how fuses and circuit breakers makes this confusing I don't understand. They are both designed to open when a circuit is overloaded. The fuse is cheaper and the circuit breaker can be reset. Other than cost I really don't know if their is a reason why engineers choose one over the other. A circuit breaker may work better if when the circuit is activated and an overload exists temporarily it can be adjusted for the overload easier than a fuse. I have seen slow blow fuses that were designed to allow a short overload when things likes motors were started. When you start some electrical devices there is a larger resistance to overcome until the item reaches full power. So the initial current is high then it drops back to operating current.
Safety might be the reason for fuses instead of CB's. In the auto many use 100,60,40, and 30 amp fuses. If you had a short to ground in those types of circuits a reset CB might increase the risk of fire.

There's nothing wrong with checking for loose connections but a loose connection, as I stated earlier usually will give you an intermittent open and won't blow fuses. He's blowing fuses when is slides are moved in and out or if he's bouncing down the road. That points to a B+ lead being grounded during the movement. I'd look at motor connections and harnesses on the slide that are being folded in and out. Wires that are located in a pinch point etc,. The first task is to isolate the problem to allow focusing on that circuit which is blowing fuses. Narrow down the circuit so you are at least looking in the correct location. That requires a systematic approach so you don't waste time chasing your tail.

Cranky I never had the opportunity to use a short finder. I don't know why but it was never suggested to me otherwise I would have used it.

TeJay

Been looking at all junction boxes, outlets and cables at or near the battery box and have not been able to locate any more loose or bare wires that could be causing the issues.

I was told by the repair person that where all the slide power wires entered the fifth wheel they were connected. I have not seen where that is so taking them apart and driving around is not an option right now.

When we first got the fifth wheel the 15 amp fuse that is for the slide lights and refrigerator kept blowing with little movement.

Now after each time I take it back I guess they keep tightening screws and wire connector in an effort to solve the problem, but never actually locate something that would be causing the problems. It doesn't happen as often so no idea on where the problem is.

It took a couple hours to blow last time, so when we leave I think I will just leave fridge off and see if it blows without it on.

I realize a fuse and circuit breaker serve the same purpose. What makes it confusing is if you are looking for a fuse you might search all day and not find one, but the circuit breaker is easy to find. The circuits use very few actual fuses but there are quite a few circuit breakers. It is just using the correct terms make it easier to understand, that's all I was trying to say

According to the OP, his coach blows a fuse. There has to be a B+ wire moving around or rubbing on something to cause this. I have never checked the lites in a slide to see if the bulb has B+ to it all the time and the switch complete's the ground path. His issue very well could be a wire behind the fridge that is pinched. The fridge could be moving a little while the coach is moving. The problem he will have is finding which one. I have found over the years is the pinch can be soooo small that might not ever see it the wire.

TJay, most every car I have worked on uses circuit breakers for high amp draw motors....such as windows. seats, rear defoggers and such. Even headlamps have a built in circuit breaker in headlamp switch. You are correct that any electrial motor is a dead short until it starts to move/spin. Thats why circuit breakers work better. If DuaneG lived closer, I bet we could find his issue.