30amp blade fuse under trailer keeps blowing!!!

[TheFerg]

Hi everyone. I am frustrated and lost. Our family bought a 2022 Grand Design 265bh transcend explor and the 12v fridge/electrical has been giving us a headache ever sense. We first brought the trailer home everything was great. Then the 12v fridge stopped working. After reading all the posts and comments on this forum I decided to go fuse hunting in the back of the fridge. Low and behold the fuse was okay. But the fridge still did not work. I checked and the fridge had power. So I switched strategies and started form the battery. Ahhh ha! I found it. There is a 30amp in-line blade fuse in aweatger protected holder off the positive wire from the battery that had a blow 30amp fuse. I followed the wire and it went to the fridge wire I saw earlier when I pulled the fridge out (same color red with white stripe). I replaced the fuse and the fridge was back up and running again!

Today I headed out to the trailer to start packing our food away for our big trip next week and the fridge had no power to it. It was warm inside with no light. Back under the trailer I go on the passenger side by the “A” part of the trailer frame and that 30amp fuse was blown yet again. I replaced it with a new 30amp fuse and almost instantly it melted/blew the fuse. That’s when I said I am in over my head this is not suppose to happen.

as we all know these new 12v fridges always have power to them even when the battery disconnect on the trailer is activated. EVERYTHING works in the trailer other then the fridge connected to shore power or generator or just off the batteries.The trailer is brand new. I have called grand design and left messages with no reply’s. The dealership I bought it from said their service center is backed up and won’t look at it. I have thought of everything and need help so we can go on our annual boondock Campout with friends and family next week.

[Country Campers]

TheFerg

When tracing the red wire did you find anything else that it is attached to? Or does it go directly to the fridge. I think it may power the jack and some other things.

Brian

[howson]

TheFerg -- the 30A fuse could be related to the Solar Prep in your Transcend. Does your unit have a solar controller and a solar panel?

The 30A fuse shouldn't affect the refrigerator...I'm a bit confused on that point. Those two circuits are supposed to be separate from each other.

Do you have a multimeter and know how to use it? Can you post pictures of the wiring that's visible under the trailer (where the positive battery wire is connected to the self-resetting circuit breaker. That breaker is a small device with two posts on it and should have three wires on one post and four wires on the other post.)

[TheFerg]

[TheFerg]

Here is my power going to the in-line breaker and in-line fuse

[ncitro]

TheFerg As a test, you could pull the fuse behind the fridge (or disconnect the wire if you see another place) and replace the fuse in the tongue. If it blows again you know there is a short somewhere between the two points. If it does not blow until you replace the fuse by the fridge you know your issue is after the other fuse. As howson suggested if you have a multimeter there are some other tests you can do, let us know if you have one and your skill level with it.

Out of curiosity what size is the fuse behind the fridge? I would assume it is 30A as well?

[howson]

TheFerg

I overlayed how it should be wired (upper left) over your picture. I also overlayed (upper right) a picture of a 7-pin's wiring. What I'm attempting to show is that metal box is where the 7-pin's wiring is joined with the camper's wiring.



From what I can see in the picture and how (in my opinion based on what I can see but I could be wrong) that 30A fuse's wiring should not go into the junction box. The 30A fuse should go to the solar controller. (You didn't answer the question about whether you have a solar controller in the camper. ??? )

Without knowing your level of competence with electricity and if you have the proper tools to troubleshoot I am hesitant to post any more information. With the info in the pic above a competent mobile technician should be able to track down the issue and fix it for you.

With proper documentation you might get reimbursed for the labor charged by a mobile tech by Grand Design, but not the "service fee" mobile techs charge. That $$ will be from your pocket. (That's just the way it works.)

Howard

[Yoda]

Here is my power going to the in-line breaker and in-line fuse

howson

In the picture, lower left stud where battery attaches appears to have another terminal lying against from the opposite stud (discolored yellow next to purple). You might want to check it. Not sure what problem it wold cause other than jumping the breaker and possibly allow excess current. But I am guessing here. You also have two wires with red/white stripes that can be easily confused. One is a red wire with white stripe and the other is a white wire with red stripe. The primary color (widest stripe) is the first color in the designation. It could be the wire you think is at the fridge is actually the other one. You can use your multi meter to check by disconnect a wire at a time and checking what looses power.

Trying to help
Keith

[TheFerg]

I do have solar factory installed 165 panel and a solar controller. I have 13.2 volts at each battery. Everything works on the trailer without the 30amp in-line fuse other then the fridge. This includes the younger jack working as it should. When plugged into the truck all lights on the trailer work. The fuse blows all the time (plugged into sore power or not including with the battery disconnect in off). The fuse on the fridge (backside) is a in-line 15amp and it is good not blown. Which makes me think it is between the fuses a “problem””

Thank you everyone for the tips and help out with this. I finally got through with grand designs. I spoke with there electrical technicians and did a video call with them so they could see what I am seeing. I put the fuse in the in-line holder and it melted and popped instantly. The technician on the call said, “wow” I have not seen that before. They worked with me testing everything with the volt meter. I pulled the fridge again and checked ohms in the back of the trailer from the power wire and had none. With that finding and all the other tests I completed with them they said I have a potentially a: pinched wire, damaged wire or a wire that is going to ground or grounded out somewhere between that 30amp in-line fuse and the back of the fridge.

I pulled what under belly I could to chase the wires with no luck till I got to the slide out wires. The fridge is located in the slide so I thought I might have a damaged wire somewhere in the slide out on the under side. Damaged from putting the slide in and out. I exposed all the wiring under the slide and found a spot in the power wire that was damaged a bit (small pin hole in it. I taped it up and tried replacing the fuse again with no Luck. It blew again. It makes sense because the trailer is so new and using the slide “in and out” a lot lately could have started this issue. Assuming all the wiring was installed correctly from the factory.

I am going to reach out to mobile mechanics because the shops/service centers are “months” out. I am in a hurry and or rush to get it done before our big trip next week. A fridge is essential for our family to keep meds cold. But if I have to I’ll go old school and use coolers if I have to.

[Jlawles2]

Just for testing, can you bypass the power from the front to the fridge (use an inline fuse) to verify the fridge is functioning properly? You may be able to take a straight quick connect crimp and plug into the downstream (fridge) side of the 15A fuse with an auxiliary battery. Ensure that the aux battery used is hooked to the chassis of the camper.

if that passes, with the front 30A removed, reverse the connection point at the fridge. This if the fuse blows this will confirm that there is an issue with the wire. Although you should be able to OHM between the upstream side of the fridge 15A fuse and the chassis and get a reading if there is a direct short.

Did the tech have a list of everything on that circuit? It could be one of the other items powered by the fuse is the issue, something like the gas detector, or possibly the stove top spark system.

[Shady5615]

I came across a similar post in another forum and it triggered me to look on this forum for folks who have had a similar problem. I'm curious if the OP ever got it resolved.

I had a problem that sounds the same as described in this thread, but in my case I found a spot where the power supply cable had a splice in it just before it entered the slide out. The insulation on both the + and - sides of the cable had been stripped back too far exposing bare copper. My suspicion was that they got close enough from time to time that they shorted and blew the fuse. I cut out the splice and remade it and had no problems since then.