Powering up a dead fused circuit

[kartvines]

OK I now have a wire that is no longer providing my fuse box with power, due to a short. Being I have not been able to follow the problem wire far enough to locate the problem, and I have also not been able to locate that wire on the inside of my dash before it go to the fuse block. I have been unable to make the needed repairs.

So I was wondering, there is a device called a "Add a circuit" which allows you to pull power from a fuse to provide power for something else. I was thinking I could pull a new power wire from my battery and with jumpers wires I can use this "Add a circuit" in reverse, and power up a dead circuit in my fuse block to again have power to those items, my radio, windshield wipers and heater control module, by powering these fused circuit with a new power source.

Does this make sense and or sound reasonable? At least until I am able to locate and repair the shorted wire that is creating my current problem?

[RV Wizard]

Have had to pull a new circuit or add a ground many times on coaches that have a short. Check the loads to be sure they are not what is shorted out and blowing the fuse first.

[kartvines]

Originally Posted by RV Wizard

Have had to pull a new circuit or add a ground many times on coaches that have a short. Check the loads to be sure they are not what is shorted out and blowing the fuse first.

Thanks for the feedback, as far as the load, are you referring to the fuse, and the wire leading to and from it? How do you test the load and from what point? Currently the fuse has zero power to it base on a test from either side of the fuse tips. I have not yet checked the other circuit but I will prior to adding power to them.

Have yo ever powered up a load from the fuse panel itself? If so did yo do it in the manner I am considering? If not how did yo locate the connection yo had to splice into? I still have not been able to trace the wire far enough to discover the case.

[bldrbob]

Some fuses are fed thru the key. No power when the key is off.Some panels are fed with a fusible link which is a section of wire desiged to protect the circuit.

[kartvines]

Originally Posted by bldrbob

Some fuses are fed thru the key. No power when the key is off.Some panels are fed with a fusible link which is a section of wire desiged to protect the circuit.

The shorted wire is a switch fuse items, so those was only power to those fuses when the key is on, how does this change my direction when it comes to finding least a temporary solution to my short?

I assume that I can add a new power wire to that fuse and then that circuit will be complete again and provide power to the powerless area.

If the circuit is fed thou the key will the shorted wire have to intersect with the key connection , Or is it just the way the fuse panel is wired and I still need to concentrate on the fuse panel?

[ahicks]

"my radio, windshield wipers and heater control module"

This would have to be quite a circuit. It would be pretty unusual to have one fuse feeding all this equipment. I would bet this isn't actually the case.

Something to consider when doing what you're talking about, before you go to that trouble, is whether your short is in the wire leading to the appliance(s), or if it might be one of the appliances itself? For instance, if the wiper or heater blower motor is bound up somehow, they're capable of causing enough draw on the system to blow even a 30 amp fuse. If the appliance itself (or one of them from what you're saying) is defective, running a new circuit isn't going to fix a thing.

So assuming you're right for a moment, and all that stuff is on the same circuit, you could disconnect all (at the appliance end) and see if you still have the short. If you do, then running new circuits would be justified.

I would NOT put them all back on the same circuit. The reason is the radio wiring is very small, generally is rated for less than 5 amps, the heater is generally 30. To have them both on the same circuit would require a 30 amp fuse, and if there were a problem with the radio wiring, you could have a fire....

[kartvines]

QUOTE=ahicks;829680]"my radio, windshield wipers and heater control module"

This would have to be quite a circuit. It would be pretty unusual to have one fuse feeding all this equipment. I would bet this isn't actually the case. Not on the same fuse but it seems as if the wire that feeds these items was a single wire. Everything worked the week before, and I am not 100% positive that the single shorted wire supplied the power to all of these items, being I never ran them at the same time, but when this wire was no longer working at least these items no longer worked.

Something to consider when doing what you're talking about, before you go to that trouble, is whether your short is in the wire leading to the appliance(s), or if it might be one of the appliances itself?
How would I test the appliance itself? The windshield wiper would be easy but when it comes to the radio and heater control , it is all but impossible to get behind either of these to run a test wire. Again I had tested each of these within a month and all seemed to work great.

For instance, if the wiper or heater blower motor is bound up somehow, they're capable of causing enough draw on the system to blow even a 30 amp fuse. If the appliance itself (or one of them from what you're saying) is defective, running a new circuit isn't going to fix a thing.
Again I am only assuming that this is the problem, since I discovered the shorted wire, these items all failed, so I assume it was all due to this single short. All of my other devices seem to work correctly so it is only an assumption. Otherwise I must then assume that the only problem I discovered is not the cause of all of the current problems and instead of a single short I have multiple problems instead.

[H. Miller]

You've not said but are there several fuses in the "fuse block"? One for each appliance? Are any of them blown?
My bet is the key (starter) switch is bad.

[kartvines]

Hopefully I am grasping what you are trying to say so, how would a wire that you feel is shorted (to ground) BEFORE the fuse affect the fuse??? It can't! Is the actual fuse blown (by visual inspection)?
When I bought this MH all of the power wires wee added to the positive post of the battery, and in order to clean this mess up I installed a secondary fuse block under the hood next to the battery banks, to make is easier to identify any problem that would develop and each of the wires that was merely attached to th positive post of the battery was now fused

If so, then something AFTER the fuse is causing the problem and is probably one of the appliances powered by that fuse.
When I first discovered the problem it was due to the devices not working, then I went to the fuse block I installed and discovered that the fuse was blown. I added a large amp fuse gong form a 5 to a 10, when I then discovered that the wire was now overheating. It went so far as to melt the fuse block where the the wire as attached to the terminal

Disconnect the battery - turn on the vehicle start switch with all appliances OFF - with an ohm meter connected between the fuse and a good ground turn on each appliance until one "grounds" the circuit.
With this wire being shorted, none of the mentioned devices works at all, so how am I able to test the circuit, and when this circuit comes in contract with power it arc [sparks when it comes in contract with the positive battery post] I hear a click, which also confuses, me like it is connected to a solenoid or something that is now being activated, at least that is similar to what I expect to hear in a similar situation.

That's the offending circuit...........Then you can start running additional circuit wires after determining that it isn't the appliance its self. Take the old wire out (disconnect) as it may become a fire hazard.

H. Miller you may notice I also added the post you deleted because I thought it was a good question and by answering it my allow other to see my position.

Originally Posted by H. Miller

You've not said but are there several fuses in the "fuse block"? One for each appliance? Are any of them blown?
My bet is the key (starter) switch is bad.

I have not yet tested the other fused, being I wanted to pull away for the task before I create more problem for myself, I will have the week end to try and troubleshoot the problem myself before I will end up taking it to a mechanic to repair the problem for me, which will not only cost me way too much but it will not allow me to solve the problem myself and know the root cause. Being this seems to be the only way I learn.

When I installed the separate fuse panel, I cause myself so many problems,[and headaches, and a month of troubleshooting and repairs] and I was really proud of myself when I fixed all of the problems, myself, and as I said everything was working perfectly, at least that is the way it seemed.

I would prefer to locate and then repair the problem myself, again it seems as if I alway learn more from my mistake than in any other way, and this has me puzzled, and the distance between the battery connection to the root problem is so far apart that too is causing me grief, because of not being able to trace the offending wire the full length to discover the root cause and allowing me the ability to make the proper repair and not just patch it .

I have a serious mental problem, I am not only anal but I tend to over-think everything, so I am not able to look at it as simple repair job, instead it become a major issue. I am unable to let a task go without knowing or understanding what was truly cause it, and know that I did all I could do and it was done correctly.

[ahicks]

OK, I think where you are at is becoming a little clearer. You ARE talking about a circuit. It's powered by the ignition switch, and is only hot when the key is turn on or to accessory?

If that's the case, I would check the circuit at it's beginning to see if it's powering up when turned on - at the ignition switch. From there I would start checking the chassis fuse panel which is where that wire goes. The chassis panel is where that circuit is split, fused, and distributed to the radio, wiper, and heater circuits.

[RV Wizard]

I think you have an open circuit rather than a short. If none of the fuses or circuit breakers are blown or tripped; you do not have a short. I, however you have several fuses in a fuse block that have no power getting to them (even with the key on) you probably have a bad relay feeding that section of the fuse block. If the ignition switch is sending power to the relay coil but the power does not connect to the load; the relay is defective.

[kartvines]

Originally Posted by ahicks

OK, I think where you are at is becoming a little clearer. You ARE talking about a circuit. It's powered by the ignition switch, and is only hot when the key is turn on or to accessory?
Correct

If that's the case, I would check the circuit at it's beginning to see if it's powering up when turned on - at the ignition switch. From there I would start checking the chassis fuse panel which is where that wire goes. The chassis panel is where that circuit is split, fused, and distributed to the radio, wiper, and heater circuits.

So what you are suggesting to pull the ignition switch and try and locate the wire there? So the problem wire is routed to the switch before it is routed to the fuse panel? I had thought that the switch was wired to sections of the fuse panel directly and then sections off to those switched fuses.

[kartvines]

Originally Posted by RV Wizard

I think you have an open circuit rather than a short.
I must admit I do not really understand the difference, regardless it is a wire that is no longer deliver power to the load, I began to rethink the situation also and now believe the wire must have ground itself, because why else would it arc when it comes in contact with positive battery post,doesn't that mean it is now grounded?

If none of the fuses or circuit breakers are blown or tripped; you do not have a short.
That is not correct, as I mentioned in other posts, it doesn't burn out the fuse in the stock panel instead it blow the fuse in panel I installed at the battery positive post, I pulled all of the wires from the post and diverted them to a stand alone fuse panel and then rerouted it back to the positive post to cleanup the rat nest of wiring that I discovered after I bought her. It has been months since I installed that panel and until last week end everything had worked correctly and I had no short, and also taking into consideration that the wire in question must not have pulled too many amps, because prior to this problem everything was working correctly protected by a 5 amp fuse.

I, however you have several fuses in a fuse block that have no power getting to them (even with the key on) you probably have a bad relay feeding that section of the fuse block. If the ignition switch is sending power to the relay coil but the power does not connect to the load; the relay is defective.

I guess a bad relay is possible, but where would it be located so I can check it, and how would you troubleshoot a relay, I have never done that before. I do hear a click so the idea there is a relay in line would explain that clicking, but I have never seen one and as I said I have no idea where it would be located.

Please explain what you mean by an open circuit. Then how to make that repair. Since I have gotten involved in restoring vintage travel trailer and now this vintage motor-homes I find that people often use a word or phases that means one thing to them and may mean something completely different to someone else, and as you have clearly discovered I am of the camp that there is no such thing as a stupid question, the only stupid question is th one not asked, so I am hoping that those of you whom are much more skilled in this are can direct me so I am able to learn from you and make this repair by myself.

[bldrbob]

Sounds like you installed a separate fuse block with a bunch of wires that were connected directly to the battery.The wire you used is not large enough to carry the combined load of all those wires and is heating up.A 10 amp fuse is not large enough to carry the combined load and burns.The feed line has to be big enough to carry the combined load.