I'm new to RV'ing and towing a towed vehicle. We recently purchased a 2015 Cadillac SRX for our toad. It was previously used as a toad with a Falcon 2 tow bar, an air system hookup for braking, and 6 pin wiring for electrical connection. It's obvious the 12V from the coach is NOT charging the toad as we have reached our destination with a dead car battery a few times now. So not only is the black wire not in use, but the blue wire is also not in use as that is for electric brakes.
My question is can I use the black center wire from the 6 pin and tap into a 12V wire at the back of the coach? If so, do I need to add any fuses to make this a safe operation? We are 4 weeks into a 7 week trip, but I'm tired of dealing with a dead battery. Thanks in advance, for any help.
Yes if the black wire is not in use it is fine to use as a charging wire and it is recommended to use
fuses at both ends.
John, I addressed the same issue.
I took care of it in a relatively simple way. As I always drive with the coach lights on, I just tapped into the coach tail light circuit and ran that wire ( through the 6 pin plug ) to the positive terminal of my toad battery.
Now, whenever I'm whenever we're towing the toad, the tail light circuit keeps my toad charged. And yes, I did add in inline fuse in the circuit. It's been working fine for 5 years now, no issues.
If you prefer not to drive with your coach lights on, you'll need to find a hot only when ignition is on circuit to tap into.
John, my 2015 SRX tows just fine with 6 pin lights and brakes connection, no charging hookup.
Put car into Park, turn motor off, depress latch and place into Neutral. Never had a battery problem since 2015.
All the best
I tapped into the factory hot with ignition wire, fused it before the converter and then fused it at the car. I have the Brake Buddy and it has an electric air compressor and needs charging wire to work.
If using a 6 pin trailer connector and it is wired properly on the coach the center connector should have 12v on it. That is what I used and put a battery maintainer which is fused between the coach and car battery.
Amazon.com: Hopkins 39332 Brake Buddy Towed Vehicle Battery Maintainer :... (https://www.amazon.com/gp/product/B004RCXB8A/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1)
Have you checked your cars manual to see if the battery should be connected or dis connected while towing?
I like the following setup for charging the toad battery when the coach engine is running:
Fuse at both toad battery and "source of coach chassis battery connection". Amp rating depends on gauge of wire.
40 amp standard automotive relay:
IN from and chassis battery source (on many coaches the closest to the rear of the coach is the chassis battery lug of the battery isolator which is connected with large-gauge wire to the chassis battery, but any source either at the chassis battery or a place connected with large gauge wire works equally well).
OUT from relay to coach trailer connection
Any ignition hot source to close the relay. And lastly ground to complete the circuit to close the relay.
I use 8 gauge wire for both the hot and the negative from battery to battery for less voltage loss. And make sure your ground/negative connection on the coach side is either to a good connection to chassis battery negative OR good clean chassis steel.
And, if you want the toad battery charged even with the ignition off, just delete the relay. So fuse at both batteries and 8 gauge wire.