Fuse Blows Repeatedly

[Dawn]

Hi LTVers,

In the past 5-6 weeks, fuse #1 (front living area -- includes the AC control panel and the igniters for the stove burners) has blown 3 times...

I have protection on the box (Progressive Industries) and no error codes there.

Have not overtaxed the circuit. At most, AC + TV + a reading light (if there are other, hidden, power vampires on this circuit, I don't know what they are).

Any thoughts as to what might be causing this?

thanks,
Dawn

 

[autostaretx]

Could be wiring harness damage.... has anyone put a screw through a wall/panel for some odd purpose?
(installed harnesses can also chafe against some hidden sharp edge of metal)

Does the fuse blow instantly (thus an ohmmeter may be able to track it down), or only occasionally (usually while driving... as vibration causes the (theoretical) exposed wire(s) to touch metal)

--dick

 

[alichty]

Not certain what would be causing this but any time a fuse blows consistently it is trying to warn you about something. Don't ignore the warning. Something is definitely wrong.

You could try calling LTV and asking what else might be on that circuit - they could save you some time trying to trace down what else could be involved besides the items you have already identified.

 

[TStiles]

Wow... These can be tough to diagnose, especially if the fuse doesn't fail immediately when replaced. Hopefully, you will find something as simple as a connector that has loosened and is touching/grounding with vibration present. But you never know. It could be that insulation has been worn off somewhere. When confronted with these situations in the marine environment, I found that isolating single sub-circuits before diagnosis always helped. Coaches are a great deal like boats with moisture, vibration, and construction imperfections all becoming your enemy. Best of luck on this one. As alichty suggested, a call to Triple E might help. Perhaps they've seen a pattern in other failures that can provide a starting point, at least. Keep us posted. We'll all learn from your discoveries.

 

[Dawn]

Thanks, everyone. It doesn't blow as soon as a replacement fuse is inserted, so I guess that's the good news. I think it's driving that's doing it, but not every drive. I'm going to see what happens when I drive the rig again on Friday...

 

[autostaretx]

Since you're dealing with a 110 vac problem, be aware that it could be feeding hot voltage to your Sprinter's grame, leading to a potentially dangerous condition when you step outdoors completing the circuit from the Sprinter to earth. (especially on rainy days).
((this would be if/when you're on shore power))

The "blows the fuse" may be passing low current (still enough to be deadly) at all times that 110 vac is present

I'd be all over it with voltmeters and ammeters trying to find out what's happening.

--dick

 

[Klipstr]

If it's a "fuse" and not a breaker, then it is a 12V problem so that makes it less dangerous.

 

[Dawn]

It's the 15 amp fuse that's blowing, none of the breakers are tripping.

 

[irvingj]

From my old wrench-slinging days, maybe this could help: Have a close look at the blown fuse. if it appears to have exploded --bits of melted metal around on the inside, along with some blackening-- then it's a dead short. If the glass (or plastic) is clear but the fusible bridge looks like it simply melted, most likely an overload.

 

[Dawn]

IrvingJ

Thank you, if/when it blows again, I'll examine the fuse more closely.

 

[Dawn]

Howdy all,

After weeks of driving and no issues whatsoever, during which I have to say that frankly, I mostly forgot about the fuse (and when I did remember, didn't want to tempt fate by posting that nothing had happened), it was blown when I made camp last night. And in contrast to previous blowouts, it now blows immediately when I try to replace the fuse. To IrvingJ's point, it looks like a dead short not an overload.

I took the drawers out and got my head in there along with a good light and cannot see a single thing that looks wrong. Sheathing still intact on everything I can see, the grounds are all attached. Guess it's time to take it to the repair shop.

 

[Dawn]

Update after troubleshooting with Willie at LTV -- propane switch in compartment and/or wiring harness for same and/or switch on the propane tank itself are faulty. Have an app't for repair on Monday!