dbs944,
Well Sir, while I'm certainly no expert on this stuff, it always intrigues me. If I may, lets start from the beginning. First, is your motor home a "three filament" system or a two filament system? That is, do you have "amber" turn signals on your coach or, are they just red?
If they're amber, then sometimes the factory installs a "converter" prior to the 7-pin plug on the back so that, what you see in the plug is a combination signal from each of the right and left turn pins. That is, a turn signal going to the left pin on that 7-pin connector will blink. And, it will do the same for the right pin, when the right turn signal is triggered from the drivers seat.
OK, but, if the brakes are applied, then you get a brake light signal from both of those, left and right turn pins. Some or all of this you may already know so I hope I'm not sounding too fundamental here but, I like to have a clear picture for both parties so analyzation can be understood easily by both parties.
So, again, you have a running light pin, usually a brown wire attached to the back of it, but not always. Then, you have a left turn with, I think, a green wire attached to it, and right turn pin with a yellow wire. But, it's been a while so, my colors might be off.
Now, may I also ask, are you using the stock tail lights/bulbs on the toad? If so, I think that's a great idea, I've done it that way for decades. Some like to add new sockets and bulbs but, that's just not for me. Anyway, your issue may or may not be related to a shorted strand of wire behind the 7-pin plug on the coach. So, while you may have had it apart prior to this, my suggestion is, dig into the back side of that plug and make sure there's no stray strands of wires in places they shouldn't be. If you have to, and, if there's enough wire in the entire cable, then cut off all of it and re-install all new ends into the back side of that plug.
Then, do a pin test. If you're still getting "Cross-fire" in there, it's way before the plug on the coach, hmmmmmmm. Not sure on that one. But, in any case, you want "definite" clear and precise signals to each of those pins in the trailer plug. As you know, once that's free and clear and all working correctly, then you can proceed to the toad with the wiring.
Now, just by chance, you may also have a 7-pin setup that's different from others. That is, you may have a proprietary, dedicated RIGHT and LEFT pin in the plug and, a dedicated "BRAKE" light wire. That makes it real easy to set up a foreign or, domestic toad that has amber turn signals and, the owner decides to utilize the stock tail light bulbs. So, let us know what you have and what you've found out so far. Interesting.
Scott
P.S. I'm including a wiring diagram I drew up for our '11 CRV when I wired it. Take a look and see if it's close to what you're attempting. Our CRV when towed, and the lights are activated, looks just like it does when we're driving it. Amber turns, all three brake lights, running lights etc. It's a piece of cake to wire it that way.
Scott
