Where do I connect this wire?

[losfeliz]

In my 1981 Excella, I am replacing the original Triad-Utrad TU-570-6 Converter Charger with a Progressive Dynamics PD9270. In the old converter, there were three wires that entered the unit - pos, neg, and a smaller gauge mystery wire with black insulation that connects to the "POWER ON WHT" fuse. This is not the ground, as it attaches to the outside of the unit and is uninsulated. I don't know where to connect it on the new PD9270 (I asked Progressive Dynamics and they were no help). In the pictures, I've added arrows to the mystery wire. I think, but am hoping one of you can confirm that, it needs to be attached to the negative terminal on the PD9270. As you can tell, I disassembled the old converter and put a question mark where the mystery wire connected.

[uncle_bob]

Hi

Whatever that second black wire is, in the second picture it looks like it is in pretty bad shape. If that's the case, I'd run it back to the other end. It may be worth replacing the entire wire.

Bob

[losfeliz]

Originally Posted by uncle_bob

Hi

Whatever that second black wire is, in the second picture it looks like it is in pretty bad shape. If that's the case, I'd run it back to the other end. It may be worth replacing the entire wire.

Bob

True. I messed it up pulling it from the old converter. It's not frayed beyond that section so I plan to just trim it back to where the wire / insulation are sound. Removing from the old converter was a bear!

[mehes]

Do you have an indicating light on the panel that displays tank levels? I believe that black wire leads to the indicating light. Its been a while since i replaced the univolt in my 345 Classic motor home but I believe the univolt had a separate winding that would output low voltage AC for the Power On light. I used a 120 volt relay that would feed 12 volt dc to the light when 120 v ac was available. You don't want to just tie the light into the 12 volt positive line as the battery would keep it illuminated all the time. If the Power On light is not that important to you, tape up the black wire, connect the heavy positive and negative leads, connect to the ac supply and you are done.

[losfeliz]

Yes I do. So if that is it, does it connect to the negative on the new converter? It looks like it did on the old one (3rd picture).

[AtomicNo13]

I think it might be the wire thad feeds the power indicator above the stove, in the monitor panel.

[Lumatic]

Ground to frame?

[mehes]

Originally Posted by losfeliz

Yes I do. So if that is it, does it connect to the negative on the new converter? It looks like it did on the old one (3rd picture).

I don't think it will work tied to the negative. I believe you will find the other side of the indicator bulb is tied to chassis ground (same as negative). Tying to the positive will keep the light on even if you are not hooked up to shore power if your battery isn't dead. Like I said if it isn't that important to you to have the indicator light, tape it off. Or you will have to resort to a relay or small power adapter to feed the indicator when you have ac power. Airstream could have made this a lot easier by using a 120 volt indicator bulb for this purpose.

[Scoutx]

What it looks like to me is a dual winding transformer with one leg of each winding being used as a center tapped transformer,(your positive) the 2 pairs of diodes provide a full DC rectification (ie 120Hz ripple) with the wire you have listed as negative for an indicator light which would illuminate when you're on shore power, but out when you're not on shore power. The negative should actually be the heat sink, which is likely bonded to the chassis then to the trailer is using the frame/skin as a common ground.

[my3sonsdad]

To the OP, i finally found your thread and seem to have the same question, however the reference wire from the Triad does not go to my fuse/distribution panel. Did you connect to the positive or negative on the PD92xx?

[losfeliz]

Originally Posted by my3sonsdad

To the OP, i finally found your thread and seem to have the same question, however the reference wire from the Triad does not go to my fuse/distribution panel. Did you connect to the positive or negative on the PD92xx?

I don't remember where I connected it, but I did find out what it was supposed to do. That wire is for the shore power light in the control panel. So where ever I connected it (or maybe I didn't at all) now that little light doesn't illuminate when I'm plugged into shore power. Not a big deal, but the next time I'm down in there again I figured I'd play around to figure out what might make it work properly.

[my3sonsdad]

Thanks! I was able to find several other posts that are related. The wire is from a shunt inside the old Univolt which is not replicated in the modern charger/converters so most don’t do anything and go without the shore power indicator light.

[TG Twinkie]

Originally Posted by my3sonsdad

Thanks! I was able to find several other posts that are related. The wire is from a shunt inside the old Univolt which is not replicated in the modern charger/converters so most don’t do anything and go without the shore power indicator light.

The shunt would have 2 wires which connect to an ammeter. I still have the old Univolt from my Argosy. I will look at it to see what I can figure out.

[Bill M.]

On my two 1988 trailers the black wire was connected to the red power on light on the main panel.

I found no easy or straight forward way to make that light work with the new converter. The light circuit ran from the DC circuit to the transformer in the old Univolt. The current flow through the light was developed between the constant 12 volt and the 12 volt AC from the transformer.

I just capped the wire off and live without the power on light.

[TG Twinkie]

Originally Posted by TG Twinkie

The shunt would have 2 wires which connect to an ammeter. I still have the old Univolt from my Argosy. I will look at it to see what I can figure out.

My coach had no ammeter. The Univolt was very simple. 3 20 amp fuses, 1 30 amp fuse and a negative buss bar.
The 30 amp fuse is where the battery and positive side of the 12 volt DC system was connected.

[Snailer]

Just helped me out, Exact same panel in my 78 and that wire had me stumped. Thanks