Using fuse box spare fuse

wa8yxm - not wrong, just a different approach and a continuation of previous posts, plus, with the advent of super cheap meters, anyone that decides to get interested in their electrical systems should get meter and learn to use it.

DougE wrote:
The easiest way to check for a circuit is to remove the fuse, probe one side of the fuse socket with the positive lead of the meter and probe the other side of the fuse socket with the negative lead of the meter. If you get 12+ volts you have a hot socket. If the meter tries to go negative you have the probes in the wrong config, swap them. No reading is a non-working fuse socket.

For blade fuses you are not even close

A test light, Ground the clip, touch the clip to a KNOWN hot wire or terminal, confirm light.

now touch the little square of metal on the top of the blade fuse (There are two one on each end) Light = Power, no need to read a meter, No need to remove the fuse from it's socket.. no special probe needed.. Just tap and go.

The "add a fuse" finally arrived and I was able to find a hot connection at the fuse panel. I found one that was, according to the owner's book, "not in use," which was powered only by the ignition key. I did find out that several of the other "not in use" fuses were not powered at all, not even by the ignition, or had no internal connection to receive the fuse. Anyway, I got my new 7 in. monitor and camera working and got all the wires hidden and out of view!!

BTPO1 wrote:

RvBill3 wrote:

westend wrote:
Do you have a test light or a meter?
Edit: you can also make your own tester using two wires and a 12V bulb or any 12V device. You could even use your new monitor. Attach one wire lead into each of the opposing blade sockets. With the two stripped wires from the fuse location held in your hand, touch the (-) and (+) to the contacts of the device or bulb you are using to test.

IMO, anyone either working on vehicle or RV electrical systems should have a meter. They are cheap enough, now, that there is no excuse not to have one. Harbor Freight sells a variety of them, the cheapest either being $4 or free when offered as a promotion..

Not sure I am understanding this correctly, so please excuse if I have it wrong. Are you suggesting that both test wires be hooked to either side of the fuse socket? That would be 2 positive feeds. One of the test wires should be connected to ground (-) and one to the fuse socket (+). Using the backup monitor as the tester could result in damage to it. I agree 100% to go to Harbor Frieght or big box hardware store and buy a cheap meter.

x2, lost me too.

OMG, I'm sorry, I was rewriting that original post and got that all mixed up. I hope it didn't cause you any damage. I've edited the post to be correct, now. I usually read through my posts a second time to make sure they're accurate but slipped up on this one. Again, sorry. Glad there were a couple of good minds on here that caught it. Thanks, guys.:o

DougE wrote:
If you go from fuse to ground that only tells you that there is power on the hot side. Some fuse positions may have the incoming hot side connected, but not the outgoing. If only the incoming side is connected however, he can use a spade connector and an inline fuse to tap the source.

He can also depending on what type of fuses he has use an "Add A Fuse". They come in plug in mini,midi,maxi style. Taps can also be purchased for round glass style fuses. JMO

RvBill3 wrote:

westend wrote:
Do you have a test light or a meter?
Edit: you can also make your own tester using two wires and a 12V bulb or any 12V device. You could even use your new monitor. Attach one wire lead into each of the opposing blade sockets. With the two stripped wires from the fuse location held in your hand, touch the (-) and (+) to the contacts of the device or bulb you are using to test.

IMO, anyone either working on vehicle or RV electrical systems should have a meter. They are cheap enough, now, that there is no excuse not to have one. Harbor Freight sells a variety of them, the cheapest either being $4 or free when offered as a promotion..

Not sure I am understanding this correctly, so please excuse if I have it wrong. Are you suggesting that both test wires be hooked to either side of the fuse socket? That would be 2 positive feeds. One of the test wires should be connected to ground (-) and one to the fuse socket (+). Using the backup monitor as the tester could result in damage to it. I agree 100% to go to Harbor Frieght or big box hardware store and buy a cheap meter.

x2, lost me too.

If you go from fuse to ground that only tells you that there is power on the hot side. Some fuse positions may have the incoming hot side connected, but not the outgoing. If only the incoming side is connected however, he can use a spade connector and an inline fuse to tap the source.

Seems like to me that you would want to probe the circuit with the black lead to the chassis or ground and the red one to the tested source. A lot of fuses can be probed from the top without taking them out.

The easiest way to check for a circuit is to remove the fuse, probe one side of the fuse socket with the positive lead of the meter and probe the other side of the fuse socket with the negative lead of the meter. If you get 12+ volts you have a hot socket. If the meter tries to go negative you have the probes in the wrong config, swap them. No reading is a non-working fuse socket.

The short answer, of the question, exactly as asked, is YES. however you ask the wrong question.

The proper question is "Do they have power when the ignition is OFF" and the answer to that is: I'm not sure (or some do some do not) use a test light to figure it out.

On my Intruder, there is an Intelletec BCC (Battery control center) and another fuse box, not labeled, front and center (to the left as you look at it of the BCC. in these boxes there are spares of the type you desire. I use one to control my jacks and the other for my LP-1.