What is the 12v relay in the stock wiring diagram?

[DaHealey]

I'm the new owner of a 2023 Flying Cloud 25FBT and getting ready to do a battery swap / converter upgrade. Before I start digging everything up I decided to see the notorious rats nest of wires under the bed for myself and - wow - people weren't joking.

Thankfully Airstream does provide some very nice wiring diagrams in the user manual. I think I've identified everything, but there's one part that has me confused. It's the 12v relay between the positive bus bar and the WFCO 12v Distribution Panel.

One side of the relay has a wire labeled 6 Ga 'Red Distribution Buss'. The other side has a 8 Ga Red (Battery Input) and a 8 Ga Red (12 Vdc Output).

Is this the relay controlled by the battery disconnect switch near the door of the trailer? Why are both 8 Ga wires coming from the WFCO distribution panel?

Finally, where the heck is this relay? I see a box directly behind the WFCO panel - is that it? Is it in the pandora box labeled '12VDC Panel' buried under the bed?

[jeffmc306]

Yes, that is the battery disconnect solenoid and is attached to the back of the WFCO distribution panel.

The 12V box under the bed is where you’ll find the rat’s nest around it. The inside of the box is okay.

[vanderwielen]

Originally Posted by DaHealey

I'm the new owner of a 2023 Flying Cloud 25FBT and getting ready to do a battery swap / converter upgrade. Before I start digging everything up I decided to see the notorious rats nest of wires under the bed for myself and - wow - people weren't joking.

Thankfully Airstream does provide some very nice wiring diagrams in the user manual. I think I've identified everything, but there's one part that has me confused. It's the 12v relay between the positive bus bar and the WFCO 12v Distribution Panel.

One side of the relay has a wire labeled 6 Ga 'Red Distribution Buss'. The other side has a 8 Ga Red (Battery Input) and a 8 Ga Red (12 Vdc Output).

Is this the relay controlled by the battery disconnect switch near the door of the trailer? Why are both 8 Ga wires coming from the WFCO distribution panel?

Finally, where the heck is this relay? I see a box directly behind the WFCO panel - is that it? Is it in the pandora box labeled '12VDC Panel' buried under the bed?

You're reading the schematic correctly. Though I have no idea way they switch wire gauges. Your converter actually charges your battery even though the relay is disengaged. So, the relay is simply to power your 12v devices such as lights and fridge. BTW, you may not need to change your converter just because you are moving to lithium. it's lithium compatible. Yes, the relay is behind the converter.

[DaHealey]

Thank you for confirming that the wort on the back of the WFCO is indeed the relay in the diagram. That actually makes keeping it in the design much easier.

What’s interesting is that when I hit the battery disconnect button on my trailer, the whole trailer goes dark. Even though I am plugged into a 120v outlet at my storage facility.

However it looks like the converter should still power the 12vdc devices off 120v regardless of the state of the relay.