Wiring issue 17' BF with a Dometic Fridge

[dmritchie17]

I have a 1996 17' CB bigfoot, the main inline fuse keeps blowing while towing, I suspect it is the fridge that is causing this, as I am pretty sure it only happens when I have the fridge in DC mode. It doesn't affect the running lights so I have no way of knowing that it happens. When we get to our destination, ultimately our fridge is no longer cold. Does anyone have any tips on how to troubleshoot this?

I imagine it is a short, but not sure how to diagnose or fix. If I run with the fridge on propane it does not trigger the fuse, even though the fridge is still drawing DC to operate.

[Jim Bennett]

It definitely sounds like there is an issue with your 12 volt system. I would look into what the problem is and correct it, or have someone do it if you cannot.

Regardless of your 12 volt issues, I would only tow the trailer using propane to refrigerate. Using the 12 volt system will drain the battery real fast.

[Jack L]

Are you referring to the in line fuse that is under the dinette by the front bulkhead? The one that is attached to the main wiring harness. I believe that fuse is a 30 amp fuse and it's possible someone replaced it with a lower amperage fuse. When I had my 94 17CB it had a 30 amp fuse.

If you have a newer refrigerator with electronic ignition it requires very little 12V amperage to ignite.

[thrifty bill]

I replaced my in line fuses with the same rated in line manual resetting breaker. Under $10, and no longer need to find a fuse.

This is not a short cut. Find the problem and correct. The in line breakers are just easier to reset AFTER you find the problem. Anyone remember residential fuse panel before breakers were common?

And FWIW, my PD 4135 has fuses for each 12v Circuit. But they are easier to get to than the old in line fuse under the front gaucho,

As far as running a refrigerator while traveling on 12V DC, plenty of threads out there on trying that. I am in the run on propane camp.

[gordon2]

Originally Posted by thrifty bill

I replaced my in line fuses with the same rated in line manual resetting breaker. Under $10, and no longer need to find a fuse.
....

Needing to replace blown fuses should be a very very rare event. A properly designed electrical system should not routinely blow fuses. I agree that the OP should find the cause of the problem and not resort to a "shortcut" to restore power.

[dmritchie17]

thanks, everyone. Yes it is the fuse under the front dinette, I have replaced that fuse with a manual resetting type, which does make it easier to reset, but doesn't fix the source of the problem. I'm not near the trailer at the moment, and I don't know if it is a 30A or what I put in. I did just substitute what was there. So, I will check that first. I typically do run on propane, just heard it's not the safest thing to do, so was trying to refrain. Besides, it shouldn't drain the batteries while running, because the truck alternator should keep the batteries topped up.

[Jim Bennett]

Originally Posted by dmritchie17

thanks, everyone. Yes it is the fuse under the front dinette, I have replaced that fuse with a manual resetting type, which does make it easier to reset, but doesn't fix the source of the problem. I'm not near the trailer at the moment, and I don't know if it is a 30A or what I put in. I did just substitute what was there. So, I will check that first. I typically do run on propane, just heard it's not the safest thing to do, so was trying to refrain. Besides, it shouldn't drain the batteries while running, because the truck alternator should keep the batteries topped up.

There is nothing unsafe about operating the fridge on propane on the go, just turn it off at labelled tunnels and on ferries.

In the vast majority of cases, and without some upgrading to the tow vehicle 12V trailer charging, it will not keep up to the draw from the fridge. I tried it in my 5.0TA with the truck and 240W of solar charging the batteries and the batteries still slowly went down.

[Doug Arthurs]

Originally Posted by Jim Bennett

There is nothing unsafe about operating the fridge on propane on the go, just turn it off at labelled tunnels and on ferries.

In the vast majority of cases, and without some upgrading to the tow vehicle 12V trailer charging, it will not keep up to the draw from the fridge. I tried it in my 5.0TA with the truck and 240W of solar charging the batteries and the batteries still slowly went down.

I have been on the road for a week now boondocking. I switch my fridge to 12v when towing and have zero problems with the battery being drawn down. When we get to our site each afternoon the battery is charged and ready to go. I am towing with a 2014 chevy silverado. No upgrades to the truck just the factory alternator.

[VK Lee]

Check the 12 volt heating element in the fridge. If it is bad/shorted, the fuse will blow every time...

[pngunme]

I towed a 2009 Casita, with my 2002 Tundra, for 8 years, using DC for the fridge.

I never had a problem with the battery draining, but I had a 6ga charge wire, from the truck to the trailer.

I have a 2017 R Pod now and the same Tundra. Can’t run the fridge on DC without draining the trailer battery. I suspect the trailer charge wire is too small and will be addressing it when I get home from this trip.

FYI While running the fridge on propane for two weeks, at 10k’, in Colo last month, the Dometic fridge quit cooling. I checked everything I could think of BEFORE checking to propane tank. The R Pod came with a single tank. I weighted the tank and still had 5lbs left. But, just in case, I drove 50 miles round trip, two days before the end of our stay, and had the tank filled. The fridge worked fine after the fill-up.

Apparently the 5lbs wouldn’t produce enough pressure, causing the fridge to undercool.

I bought a second tank and will install “dual” after this trip... I don’t want it in the back of my truck.

To the OP: if you have always had this blown fuse problem, I suspect it’s, as someone mentioned, an undersized fuse... or, as someone else mentioned, the fridge is overheating. Use an infrared thermometer and shoot the back of the fridge (outside) the next time a fuse blows. The element could be bad. The muffin fan (assuming you have one) could be bad. You may need to add baffles to better direct the fan air flow over the coils in the back. Also shoot the activator that starts the muffin fan and see how hot it gets in that area... then find out at what temp the activator activates... you may need to relocate the activator to an area that gets hotter, faster.

Living in Vegas, I added a second muffin fan that comes on at 115 degrees and baffles. Fridge runs much cooler.

[Dennis McMillan]

If you are boondocking and not charging the battery while camping then when you fire up the TV the battery is drawing high amperage & blowing the fuse.

[dmritchie17]

Thanks everyone, gives me a few things to check. And makes me not worry about running the fridge on propane while travelling, as much.

Batteries are out for the winter now, will have to pick this up again in the spring.