Odd wire at converter

[Nplocek]

Hey guys! New to the site. I've been reading a lot but this is my first post. I'm hoping to get some help with a couple of electrical issues on my '81 30P. The trailer had a lot of water damage when I got it and the PO had done some poor repairs/removing of parts to make it a real can of worms for me.

The problem is that someone added an Iota DLS-15 converter to the system so I was guessing the original charger went bad. I replaced the original panel with a Progressive Dynamics 4060 (it fits fairly well in the same hole). In chasing down the refrigerator problem I found a wire that keeps blowing a fuse (i wrote down that it wasn't fused before but apparently thought it needed one. I can be smart like that sometimes ). I thought I had everything hooked up last year so in my infinite wisdom, I deleted my pictures of the old set up. The problem is, I can't find what this wire does in the book. All four circuits are accounted for, the 110-v power on indicator wire, and the 12-v outlet circuit. That only leaves the fused line to the battery, which would make sense, except that I have 12-v battery power when it isn't connected (or fuse is blown). On a possibly associated side note, I'm not sure my batteries are getting charged. So any ideas as to what this mystery wire does?

Sorry for the long post. Just trying fully explain my situation so I can get things straightened out and go camping. TIA

[KYAvion]

Nplocek - hope you don't mind, but I split your post up so it will be easier to answer, and so responses won't be so hard to decipher. It's really two separate issues, so two threads makes sense. The one regarding the fridge is now in the Appliances forum. Also, in the process I accidentally lost Silverloaf's reply. Sorry Silverloaf.

As far as the loose wire, what exactly is happening with that specific wire to trigger the fuse being blown? What gauge does the wire appear to be, and it's a fuse that's blowing and not a breaker tripping. Correct?

[Nplocek]

KYAvion - I get splitting them up. I felt it was a lengthy post myself. I didn't get a chance to see Silverloaf's response. I hope he responds again.
As for the gauge, I'm not sure, but I believe it is the same as most of the other wires. I know it has the red outer plastic coating surrounding the black and white like the rest. I was hooking it up when there was no power and as soon as I tripped the master switch, the fuse would blow. I now see my ammeter isn't working but that could have happened when I was trying to chase the wire down. I see in the manual there is a wire that goes from the ammeter to the electrical control center but I have no Idea what it should connect to. Especially since I replaced the panel.

[KYAvion]

I'm trying to understand what's going on here, so a few more questions...

The red coated wire was not hooked up to anything, but you hooked it up to something. What did you hook it up to and where did you attach the black and white wires?

When you say you tripped the master switch, do you mean you turned ON the 12v kill switch?

Assuming that's a YES, you are saying that a fuse blew? Which one? A fuse in your 12v panel, or a fuse at the battery?

[Salty]

I'm going to ask a series of questions myself, to try to help. I'm an electrical /electronics/power guy by trade, so....
You need a voltmeter, capable of reading AC, DC and Ohms
With the wire disconnected from everything:
Measure the voltage on the wire, AC and DC to chassis ground - If I understand correctly, there is 12VDC on the wire?
If there is already power on the wire, why hook it up to the power center? Those fuses are on the supply side.By hooking up the wire, you're back feeding into the power center.
The ammeter isn't working, the one in the Avion monitoring panel, yes ? what are the odds that your stray wire goes to the Ammeter? Could it be that you removed a shunt that was feeding the ammeter?
The ammeter itself is a low current device - say 0 to 30 amps on the scale is equal to 0 to 30 millivolts full deflection of the meter. To accurately feed the ammeter you would use a shunt, which is a piece of brass that is of a calibrated resistance. ALL power would pass through the shunt, but there would be a tap on the shunt that would connect to the ammeter. A nominal value would be a 50 amp shunt with an output of 1 millivolt/amp (just an example)
If there is 12VDC on the wire, (Positive 12 I assume?) and you have accounted for all the circuits, what if you disconnect shore power. Is there still 12VDC on the circuit? If not, measure the resistance to ground. If there is still power on the wire, disconnect the batteries.
With a stray wire such as this, a tool called a toner is useful to help trace out wires. It's a two piece tool. The tone generator and the wand. The tone generator induces a signal into the wire and the wand will detect that signal and give an audible sound (tone) when you get near it. you'll want the wire unpowered to trace it.

[silverloaf]

Nice write-up, Salty.

[silverloaf]

KYAvion - I get splitting them up. I felt it was a lengthy post myself. I didn't get a chance to see Silverloaf's response. I hope he responds again.
As for the gauge, I'm not sure, but I believe it is the same as most of the other wires. I know it has the red outer plastic coating surrounding the black and white like the rest. I was hooking it up when there was no power and as soon as I tripped the master switch, the fuse would blow. I now see my ammeter isn't working but that could have happened when I was trying to chase the wire down. I see in the manual there is a wire that goes from the ammeter to the electrical control center but I have no Idea what it should connect to. Especially since I replaced the panel.

Here's how my '88 30P is wired based upon the owners manual and observation:

There are (2) 8 gauge red wires that supply power to the 12v side of the electrical panel. One is 12v power supply from the converter; the other is 12v power supply from the master control panel.

At the master control panel, the red wire is connected to the ammeter. This connection also includes the water pump switch, water heater switch and power to the tank monitoring circuit board.

An 8 gauge black wire connects the ammeter to the kill switch. The kill switch is connected to the battery with another 8 gauge black wire. A 40 amp in-line fuse is near the connection to the battery.

When operating on battery power, current flows from the battery, through the master control panel and on to the 12v side of the electrical panel. When on shore power, the current flow reverses, sending power to the master control panel and onward to charge the battery. The battery acts like a "surge protector" when the converter is supplying the power.

When I began digging into the electrical circuitry last fall, I found a previous owner had bypassed the ammeter and joined the wires together from both sides. The ammeter had failed (not uncommon) and this was the owner's quick-and-dirty fix.

Should the ammeter case be grounded, the ammeter might have short-circuited to ground, possibly tripping a fuse. I suggest you do the same and then check the voltage at the other end of the red wire if its not connected; you should read battery voltage.

Also, there is a capacitor connected into the 12v side of the electrical panel. Should this fail or not be present, any power surge could overwhelm the fuses.