Blown Fuse AGAIN

you know that's a darn good question. If I remember correctly it was when I turned on some of the lights in the back. I'm heading out again this weeked (with extra fuses, lol) So i'll see if there is a pattern
Jim

[Wavery]

You might want to take a look at the safety switch on the rear bathroom wall. It may have a short. If it does, it will blow the fuse that controls the lights on the rear shell.

I took my trailer out yesterday to get it ready for the year and was cleaning out my fresh water tank and I turned the water pump and there was no power.

I checked the fuses and the 20 Amp fuse was burned out which is the 3rd from the top in my 2007 2720SL and it powers the water pump, furnace, toilet and bath fan. I have not used any of these since last Fall when I got my Norcold fridge replaced with a new Dometic Fridge.

I thought this would be straight forward so, I went to the auto store and got a couple of new 20 amp fuses and when I had the trailer at the park still hooked up to the car. I tried inserting the two new fuses one at a time and they both sparked and shorted as I tried to insert each of them one at a time

1)Does this mean I have a short in that circuit or could I have left something on? As far as I know the water pump, furnace, toilet and bath fan were in the off position.

2) Was it a problem because I had the SUV hooked up?

3) Do you have to have the battery disconnected or something before inserting the fuse?

4) Is it possible that the shop may have shorted these wires for the water pump when installing the new fridge and I never noticed since I have never used any of these since?

5) Is there a switch or breaker you can turn off so the you can install the fuse with the 12 volt power off or does this make any difference?

I was hoping someone might recognize what my problem might be and give me some advice on what to do other than taking it back to the RV shop.

There is a red light on now in the empty fuse slot on the panel now that I have no fuse inserted in this slot as shown in the photo.

[Barb&Tim]

Originally Posted by BigBear

I took my trailer out yesterday to get it ready for the year and was cleaning out my fresh water tank and I turned the water pump and there was no power.

I checked the fuses and the 20 Amp fuse was burned out which is the 3rd from the top in my 2007 2720SL and it powers the water pump, furnace, toilet and bath fan. I have not used any of these since last Fall when I got my Norcold fridge replaced with a new Dometic Fridge.

I thought this would be straight forward so, I went to the auto store and got a couple of new 20 amp fuses and when I had the trailer at the park still hooked up to the car. I tried inserting the two new fuses one at a time and they both sparked and shorted as I tried to insert each of them one at a time

1)Does this mean I have a short in that circuit or could I have left something on? As far as I know the water pump, furnace, toilet and bath fan were in the off position.

2) Was it a problem because I had the SUV hooked up?

3) Do you have to have the battery disconnected or something before inserting the fuse?

4) Is it possible that the shop may have shorted these wires for the water pump when installing the new fridge and I never noticed since I have never used any of these since?

5) Is there a switch or breaker you can turn off so the you can install the fuse with the 12 volt power off or does this make any difference?

I was hoping someone might recognize what my problem might be and give me some advice on what to do other than taking it back to the RV shop.

There is a red light on now in the empty fuse slot on the panel now that I have no fuse inserted in this slot as shown in the photo.





Attachment 5781

1 Yes, it is either a short or some device(s) that are pulling too much current for the fuse size that is installed.

2 Unlikely to be the reason

3 No, removing battery is not necessary - will not correct the problem

4 Yes, i suspect It would the most likely cause -- But the short could be anywhere in that circuit.

5 Not necessary, problem will still be there.



Tim

Thanks for your quick reply. I guess as you noted it is probably some kind of short. Even if I had the water pump in the on position instead of the off position I guess it should not have drawn enough current to blow a fuse, or to keep blowing fuse as I try and install new ones.

From your comments it appears it has nothing to do with any power source being on, as it appears it is supposed to be on. I don't think the RV shop who installed the fridge would have checked to see if the water pump worked or the bathroom fan worked after. Since we did not use the trailer after the fridge install, I might not have turned either of these on until this Spring.

Thanks for your help. I may take it back to the shop to have them look at it unless my brother-in-law who is an electrician comes by to visit and can find the problem.

Thanks for letting me know it was not because the battery was connected, or because the SUV was attached, as this narrows down the problem for me.

[Barb&Tim]

Maybe you should check in the fridge area to see if any wiring connections got shorted when they installed the new fridge. Tm does route a bunch of the wiring through that area. Good luck with it!

Tim

Hi Big Bear,

Well, it sounds like you’ve got your average good ol’ fashioned garden variety electrical short somewhere in your wiring. A word of caution, don’t try to install a larger fuse in order to fix the problem. This could result in a wiring meltdown and/or fire!! If everything was working ok and you took it in for electrical repair or modifications and now it’s broke, then there’s a 99% chance they created the problem. I think your best bet would be to get one of your friends, who is good at electrical troubleshooting, and have him help you find the problem.

[scrubjaysnest]

If your 07 was done like our '11 there are many chances for a short to have occurred when the refrig was replaced. I ended up re doing all the wiring in the refrig compartment.

You have a short to ground. You will need to troubleshoot all the circuits related to that fuse. If you do not have any experience doing this I recommend getting someone who does.

If you are a DIY type of guy and you are comfortable using a multi-meter you could safely do a little troubleshooting yourself. All power MUST to be disconnected (battery-12vdc and shore power-120vac). After disconnecting all power you need to double check to make sure there is NO power. Using a multi-meter, set on DC Volts, attach the negative (black lead) to the main steel frame (bare metal) or to the disconnected negative cable from the battery. Touch the red lead to both sides of the holder. There should not be any power. With all power disconnected it is safe for you to do some checking. A wiring diagram for this circuit (s) would be a real help or you can physically trace the wires. Set the multi-meter to continuity and attach the negative (black lead) to the main steel frame (bare metal) or to the disconnected negative cable from the battery. When set to continuity and the two leads are touched there should be an audio tone and a continuity indication on the meter. Starting from the blown fuse holder, touch the red lead to both sides of the holder. When you get a tone from one side of the fuse holder that will indicate you have a short to ground. The tone should come on when you touch the side of the holder that is NOT leading to the battery (power source). Now it's time to trace that wire's connections (path) by disconnecting each connection and touch both ends with the red lead until you do NOT get a tone. If you get a tone when you touch the disconnected wire leading back to the battery, you have found the shorted wire. Somewhere this wire is touching ground and shorting the fuse. If you get a tone on the wire leading to the device in the circuit you need to continue tracing the path to the device. Make sure you reconnect the previous wires you disconnected. If you trace all the way up to the device and the power source wire is disconnected from the device and there is no tone on that wire, most likely the device is shorted. You can check the device by disconnecting (isolate) the device from the circuit and set the multi-meter to continuity and attaching the black lead to the metal case of the device and touching the red lead to the power terminals on the device. If you get a tone the device is shorted. To verify the device is shorted you can check the resistance of the device. Set the multi-meter to resistance and attach the two leads to the two terminals on the device and compare the resistance reading to the OEM resistance numbers (should be in the spec for the device or contact the OEM).

Koz

Thanks, that looks like great advice! It also looks fairly complicated. I will probably take it back to my RV shop and tell them the water pump did not work after they installed the fridge and get them to fix it. I was looking for a post like this when I discovered that I had a fuse shorting problem.
I am sure that even if I don't use it, this post will be helpful info for others.