Interior fuse keeps blowing
Hello, I keep blowing the number 9 fuse labeled interior lights. I'm not using the rv. Only have the freg (on electric mode) running. Originally the fuse would only last a few hours, however after the...
Forum Discussion
Putting larger or different type fuses in is never a solution, and can only make things worse. The fuse panel can handle 20 A, but that doesn't mean all the wires on that circuit can.
With that fuse out, go around turning everything which runs on 12 V on/off. Does the pump come on? Any lights? Fans? Furnace? Water heater? Make note of everything which works and doesn't. You don't have a problem with any of the stuff which works, so that will narrow it down.
I'd be suspicious of the awning motor, perhaps it's on that circuit and powered, but "frozen," so constantly drawing power. Does it get warm? Can you disconnect it and cap the wires to eliminate it from the equation? Also, the TV which isn't working. If it's a 12 V model, unplug it, maybe the power supply is bad and drawing the power. See below for how to roughly measure the current through that fuse, don't just wait hours to see if it blows again. If disconnecting the awning and TV didn't cause the current to drop, you've got more troubleshooting to do.
If there are multiple wires going into the panel, you can start troubleshooting there - disconnect all of them going to that fuse circuit. Then use your meter set to 20 V to see if there's a voltage between each removed wire and where it was connected. If you see a voltage, that wire is trying to draw current. Mark it and set it aside. Do that for all the wires going to that circuit. When done, reconnect all the ones where there was no voltage, they're not the problem.
Now you've got a wire (maybe more) which could be the problem. Some things, like a CO2 detector, will draw power but not enough to cause problems (unless they're broken).
So, take your meter, set it to the 20 V ranges, and measure across a new 15 A fuse on that circuit. Fuses have a bit of resistance, with a 15 A 3AG fuse, you'll see about 10 mV (0.01 V) across the fuse for every amp going through it. If you were blowing 15 A fuses in an hour or two, it's drawing over 15 A, but not by much. So, the meter would read around 0.15 V when the problem wire is connected. It's not exact, but if you see <0.01 V, that wire isn't the problem.
Now take the "problem" wires, one at a time, and connect them back to the circuit. You should be able to identify the one which is drawing too much. Reconnect the others and set that one aside.
Now go back and try the things which didn't work in the first test - most should be working. Whatever doesn't is broken or on the bad circuit.
With that fuse out, go around turning everything which runs on 12 V on/off. Does the pump come on? Any lights? Fans? Furnace? Water heater? Make note of everything which works and doesn't. You don't have a problem with any of the stuff which works, so that will narrow it down.
I'd be suspicious of the awning motor, perhaps it's on that circuit and powered, but "frozen," so constantly drawing power. Does it get warm? Can you disconnect it and cap the wires to eliminate it from the equation? Also, the TV which isn't working. If it's a 12 V model, unplug it, maybe the power supply is bad and drawing the power. See below for how to roughly measure the current through that fuse, don't just wait hours to see if it blows again. If disconnecting the awning and TV didn't cause the current to drop, you've got more troubleshooting to do.
If there are multiple wires going into the panel, you can start troubleshooting there - disconnect all of them going to that fuse circuit. Then use your meter set to 20 V to see if there's a voltage between each removed wire and where it was connected. If you see a voltage, that wire is trying to draw current. Mark it and set it aside. Do that for all the wires going to that circuit. When done, reconnect all the ones where there was no voltage, they're not the problem.
Now you've got a wire (maybe more) which could be the problem. Some things, like a CO2 detector, will draw power but not enough to cause problems (unless they're broken).
So, take your meter, set it to the 20 V ranges, and measure across a new 15 A fuse on that circuit. Fuses have a bit of resistance, with a 15 A 3AG fuse, you'll see about 10 mV (0.01 V) across the fuse for every amp going through it. If you were blowing 15 A fuses in an hour or two, it's drawing over 15 A, but not by much. So, the meter would read around 0.15 V when the problem wire is connected. It's not exact, but if you see <0.01 V, that wire isn't the problem.
Now take the "problem" wires, one at a time, and connect them back to the circuit. You should be able to identify the one which is drawing too much. Reconnect the others and set that one aside.
Now go back and try the things which didn't work in the first test - most should be working. Whatever doesn't is broken or on the bad circuit.
