Fuses keep blowing in my 1967 TradeWind

[jbobarino3]

I have a 1967 TradeWind. It has a 2 fuse block. I currently have been using 30 amp fuses. An old sticker says 40 amp maximum - they are hard to find. My 30 amp fuses routinely blow. And, I had a negative wire melt that led to my rear camera (it was connected directly to the neg terminal of the battery). I cannot pinpoint a short that may be related wiring directly to the battery. I suppose there could be a short somewhere else in the lighting?

Other info: Accessories I have directly connected to the battery include a fresh-water tank sensor, a gauge to read the water level, a rear camera, and a battery tester gauge. I disconnected all these and the fuses continue to blow.

I know I am kinda rambling here, but does anyone know what might be going on? I never really had this problem until this year.

I have attached a photo (I think)...

[Belegedhel]

Do they blow the moment you put them in place, or does it take them a while to go?

I would say that the stuff you have connected directly to the battery has nothing to do with the fuses blowing, but also, connecting things directly to the battery without any kind of fuse is a bad and dangerous practice.

Anyway, sounds like you must have a short somewhere. You ought to be able to run it down pretty easily with a multimeter, checking each circuit for continuity to ground.

Good luck!

[Wazbro]

They look like they might be fuses for the converter, if they are and you have a 35 amp converter 30 amp fuses should blow.
Did you have 40 amp fuses in there before you started having them blow frequently?
Do they blow when your battery needs charging or also when it is near full charge?
Also the red wire looks like it is connected to a row of 12v circuit breakers.

[jbobarino3]

Originally Posted by Wazbro

They look like they might be fuses for the converter, if they are and you have a 35 amp converter 30 amp fuses should blow. So I understand, the converter converts DC to AC and then back to DC?
Did you have 40 amp fuses in there before you started having them blow frequently? I have not used 40 amp fuses.
Do they blow when your battery needs charging or also when it is near full charge? The Battery is new and it has stayed charged pretty much near full.
Also the red wire looks like it is connected to a row of 12v circuit breakers.

Are the circuit breakers for the interior lights, ceiling fan, heater fan, water pump? See how green I am!

[Belegedhel]

OK, here is some trailer power 101:

In a "simple" configuration like pre-80's model, AC power comes into the trailer from the big 30A plug on the pole in the campground. This power runs the AC outlets, possibly the water heater, if you have an electric one, the air conditioner and the converter.

The converter changes AC to DC and charges the battery. The battery provides DC power to practically every other electrical thing in the trailer, such as lights, water pump, and furnace fan.

This DC system will also receive 12V from the tow vehicle (to charge the battery while you are towing), but otherwise, the exterior signal lights that are lit by the tow vehicle should have nothing in common with the interior DC system. The only other exception is that your breakaway switch will steer 12V DC from the interior to the electric brakes.

Back in the 60's, you typically had a very simple AC breaker box with 2 or 3 circuit breakers. The DC fuses were typically to be found on the end of the Univolt converter.

So it is a little hard to see what is going on in the picture you posted, but as the other respondent noted, it looks like you are looking at DC fuses in your converter. That row of black squares are the fuses to your various DC circuits, and in this case, they are probably automatically resetting fuses. The glass fuses that are blowing might be going to your battery, or they might be the incoming charge line, which would be consistent with your comment in the PM you sent me saying that the fuses blow only when towing.

It shouldn't be too hard to trace the wires and see where they are going. If you can get your hands on a circuit diagram from the shop manual for your year of trailer, you would be ahead in the game, but you never know what kinds of wacky mods previous owners may have installed. Also, if you are still using an old Univolt converter, it is high time to replace that anyway.

good luck!

[Wazbro]

Originally Posted by jbobarino3

Are the circuit breakers for the interior lights, ceiling fan, heater fan, water pump? See how green I am!

Yes, that is what they are for.
As Belegedhel said the converter only takes AC and converts it to DC to charge the battery and power 12v stuff in trailer. Also true that if it is original it should be replaced, over 55 years old is pushing it for electronics.

An inverter would take 12v and invert it to 120v and your trailer did not come from the factory with one.

With reading that you told Belegedhel that it only blows the fuses while towing it is important to note that the trailer to tow vehicle(TV) connection was different when your trailer was built. You should check to make sure it was properly converted to the modern standard. I use to know someone that rewired at least 3 TVs to the way his older trailer was wired instead of rewiring the trailer to the way all newer vehicles are wired.

[Belegedhel]

Yeah...I was going to mention the old weird wiring standard, but it sounds like you have been towing the trailer, so I figured it must have been OK, at least until recently.

So when those fuses blow, what happens? Do you lose all the DC powered stuff in the cabin?

[jbobarino3]

… my thanks responsewas sent prematurely! Anyway, the battery is directly connected to the bottom of the fuse box. Then from there I assume it is going to the circuits for the lights, fans (ceiling vent and small wall mount), water pump, heater fan. So yes, when the fuses blow nothing works. So when connected to AC my outlets work fine. I checked for continuity from the fuse box to all white wires (there are 4) and did not detect any open circuits. I suppose I could issues in the walls going to the various components.
I checked the two fuses in my converter (it’s a 2009 Iota Dls55) and they are good (30amp fuses).
I will keep trouble shooting. Thank you Wazbro and Belegedhel