The text below is from a Forum response to a question about Forest River internal wiring color coding. It may not apply to our Palomino.
Q: Is there a standard wiring color code for travel trailers?
There are 2 conflicting 12v standards.
Marine and automotive use red = +, black = – (ground).
RV is an offshoot from house AC. Black = +, white = – (ground).
Any pre-wired marine or car accessory will have black and red wires coming out of it. FR “electricians” will use RV wiring to complete the circuit (usually).
Should have added that instead of RV black and white wire for DC, Forest River uses striped duplex wire in the appropriate gauges. One of the wires is white, is used for “-“. The other has a color stripe (used for “+”, I’ve seen black, purple, green, blue, orange, red, yellow stripes) to indicate which circuit it’s on. I discovered this convention when replacing the WFCO converter and distribution panel.
The WFCO 8735 used in A-frames and pop-ups does not allow for removal and replacement of just the converter section – the whole panel gets replaced. WFCO has a range of colored pigtails (+ wires) coming from the DC fuse section. Inside the converter is a label of what’s on the circuit for each color wire – which I found to be accurate in both A-frames. For each circuit, the colored pigtail was joined to the striped wire used for that circuit. All the white wires were wire-nutted together in a series of wire nuts behind the converter, with a 10 gauge white wire going to chassis ground on the frame.
When I replaced the converters, I replaced the wire nut series with a bus bar. The replacement PD converter/panel used the red/black 12V convention. Each DC circuit/fuse had a red (+) pigtail, and there was a single black ground from the converter. So my (-) bus bar has some white and some black wires on it (the CO/propane detector uses red/black) but no striped wires. The red wires connect to striped wires of the color for that circuit.
The wiring the dealer added for the batteries can be either red/black or black/white. Also, tongue wiring on A-frames is done by the dealer, so what standard is used depends on the dealer.
Can’t say the bigger RVs are wired the same, but these “standards” are what I found consistently in 2 A-frames made in 2014 and 2018. As was said, a volt meter is a useful check to make sure the wiring was done the way you think it was done.
just my experiences
now 2019 Flagstaff T21TBHW A-frame
prev 2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time