Adding a Toad Charging Circuit to Trailer Connector

[BobC]

For my toad (2011 Honda Odyssey) I need to make sure the toad's battery is kept charged and the key is in the ACC position or I will have transmission problems.

According to the wiring diagram my 2002 Suncruiser (Workhorse chassis) came with a 6-pin trailer connector with no 12V charging supply.

One of the former owners replaced the 6-connector with a 7-pin connector (which I need) and, although it does have a wire connected to the 12V charging supply terminal, there is no voltage present even when the engine is running. The wire (yellow) disappears into a wrapped harness and I have no idea where it goes. I think it might have been the original trailer brake wire which has been replaced with a larger gauge wire, the original looks like it's 14 gauge. I can find it on the automotive light wiring diagram and it's coded "TR" but it terminates into a block that says "to chassis wiring". I can't find where it shows on any of the other diagrams. I've checked all the fuses (under dash and under hood) I can find and they're OK.

It's probably going to be easier for me to run a new 12V supply to the connector than trace the old wire but I was wondering where best to connect it to my 12V supply so it's only active when the key is on and is properly fused. Also, what gauge wire should I use? I'm using an RVI Towed Battery Charger rated at 10A.

One idea I had was to attach it to the 12V supply going to my trailer brake controller, which I won't be using with my toad.

I've also thought about removing the brake controller completely, using it's wiring for the 12V supply and worry about re-installing it if I ever need it. I'll probably never tow a trailer with brakes, but who knows?

Suggestions?

[thompwil]

Yellow is usually for left turn signal/brake light. I wonder if the guy who replaced the round 6 with the 7 used the standard wiring pin-out for the 7, or just made up his own???

[l1v3fr33ord1]

BobC-

I'm the kind who would continue tracing the wiring until I knew what was connected to it. I have a small wire tracer that helps with this task.

That said, it's perfectly reasonable to repurpose the 12V supply to the trailer electric brake controller and the "blue" controller output wire for a trailer charge line. Be aware, though, that sometimes the 12V supply is "on all the time," not switched by the ignition.

Here's my suggestion: Take the trailer electric brake controller wires (all of them) and terminate them on a terminal strip mounted somewhere under the dash where you can get to it later. then, simply connect the 12V supply to the "blue" output wire with a jumper. In the future, when you want to re-install a brake controller, the wiring is right there to do it.

I did this on our Monaco, for different but similar reasons. It works well. I used a "European" terminal strip, the kind with the contacts protected by plastic.

Note: I believe a number of Workhorse chassis did not come with the "blue" wire running from front to back. Wire tracer helps here, again.

If you'd like more info, or want to chat about the details, send me a private message with your contact info (e-mail and/or phone).

[powercat_ras]

You can get 12 volts to your toad for charging using either 6 pin or 7 pin connectors. The 7th pin is used for backup lights which can be present on larger trailers.

If you buy a ready made 7 to 6 cable note that there are two "standard" ways that the 6 pin end can be wired so check to see which way "A" and "S" pins are wired.



The image below shows a FRONT view of the way Winnebago wires 7-way connectors on their RVs that come with them from the factory. Note that it is same as above on the 7-way end.

[l1v3fr33ord1]

BobC-

I am doing some more research on your behalf. One thing I have found is that "TR" is the backup lights circuit in the Winnie world. Have someone stand on the brakes and put the coach in reverse, then test for 12V on that pin.

I think I can figure out where the circuits terminate on the Workhorse side. Will report back.

<edit>OK. According to the diagram you have (link here), sheet 3, Winnebago terminated wires on the original 6-pin socket as follows:

Marker (Parking) - MM
Ground - TP
Left Turn/Stop - SD
Right Turn/Stop - SC
Backup (Reverse) - TR

All were 14 AWG, and yellow. Winnebago did not wire to the trailer electric brake controller pin. No 12V supply wire is listed.

By 2009, the last year of Workhorse chassis production, Winnebago had switched to a 7-pin connector, and terminated both trailer electric brake controller and 12V supply wires on that connector. See drawing here (different submodel), sheet 4.

If you have a working trailer electric brake controller, and it terminates on the correct 7-pin connector pin, then we can assume that the owner who changed the connector ran a new wire to the front of the coach. It is a different gauge and color, yes? At the same time, it is logical that he moved the backup wire to a different pin rather than let it hang loose. He should have picked the center pin of the 7-pin connector to terminate the backup wire, as this matches the standard.

Run the test I indicated above. If you have six wires and the "TR" is reverse, you will need to run a new 12V supply wire from chassis battery to hitch connector, either through a fuse you install or one that is already there, or repurpose the trailer electric brake controller wire, as discussed.</edit>

[BobC]

Everything works on the 7-pin connector except the 12V Aux/Charge, including the back-up light.

There are six original wires plus the new trailer brake wire added by the previous owner going to the 7 pin connector. This is puzzling since the 2002 wiring diagram shows only five wires going to the 6 pin connector.

Originally the back-up light wire was dangling which I connected to the center connector and verified that it works as it should.

The extra, original wire (yellow with tinned end) is connected to the 12V Aux/Charge terminal of the connector but it's dead. I haven't been able to figure out what this wire's original purpose was or why it's connected to the 12V Aux/Charge terminal. I checked all the fuses under the dash and under the hood and all are good.

I was able to confirm that the trailer brake controller is getting it's power from the CB radio circuit (15A fuse). This feeds the new trailer brake wire when activated.

[l1v3fr33ord1]

BobC-

Do you by chance have an LED or bulb on the dash that doesn't look OEM?

[BobC]

Only the one I added to indicate that my toad braking system is activated.

[l1v3fr33ord1]

Bob-

Well, I don't know what to suggest other than a wire tracer and a search.

I'm all for "standard," but there's nothing saying that you can't do what you proposed: Connect the charge line on the toad end to the trailer electric brake pin on the coach end, then jumper the trailer electric brake controller input (i.e., CB power) to the brake controller output "blue" wire. That would give you a path and a fused 12V source. This also has the benefit that you're not doing anything funky to the coach hitch connector. Just document what you've done.

By the way, did you run a new wire from the rear of the coach for the brake notification light? I assume so, or you would have used something like the blue wire on the hitch connector for that.

[BobC]

I'm just headed out to the store to get some wire. I'm going to run a new wire for the 12V supply and attach it to the CB power. And, as you suggested, I'm labeling the wires and documenting everything, including the fuse, right next to the fuse panel and, additionally as an addendum to my manual. Rather than continue to splice into the CB supply wire, if I can buy a suitable terminal block, I'll do this all right next to the fuse panel so it's easy to see and label what's going on.

I'll just dead head, insulate and label the mystery wire. It must go somewhere but I need to get this ready to tow and don't have the time to trace it.

The wire for the brake notification light is new (it came with my ReadyBrake) and goes all the way back to the hitch where it plugs directly into the ReadyBrake. It gets it power from the CB power as well, but it's only a tiny LED, so I'm not worried about its current draw. In addition to not flashing if my ReadyBrake malfunctions, if the CB fuse blows, this LED isn't going to flash as I brake which will also alert me that my toad isn't receiving a charge.

I may, do something more elegant in terms of an alarm or something but that will be a little more complex. I'd want something that's "off" if all is OK so it would need to involve a relay or something along with a separate power feed. It would be even safer if this came from the toad battery itself.

It's nice that Winnebago provides the wiring diagrams but it doesn't help much in projects like this when the wires all disappear into wrapped bundles and connectors without any labels on the wires themselves.

I'll never hook up a CB but I am a ham and would like, at some time to hook up a VHF/UHF transceiver but I'll cross that bridge when I come to it.

Thanks for your help.

[BobC]

I've done some more research and, as I suspected, the CB supply (15A fuse) is woefully inadequate for either the brake controller, which requires a 20A - 30A resettable breaker or the trailer charge circuit which also requires a 20A - 30A resettable breaker.

For now, I'm going to disconnect the trailer brake controller until I can wire it properly and use the trailer brake wire the PO installed as my 12V Aux/Charging wire, connecting it to the proper pin on the 7-pin receptacle. The existing 15A fused CB circuit should be adequate for the time being since I'm installing an RVI Towed Battery Charger in my toad which charges at 0 - 10A and has its own fuse.

My long-range plan will be to properly install both with the appropriate sized resettable breaker and relay. I don't know yet if these can feed off a common breaker and relay. The relay will ensure the circuit is turned on/off via the ignition switch.

Does anyone know how this is done on newer rigs?

[old_engineer]

What I would do is run a new line directly from the battery into circuit breaker and relay. I would use a piggyback fuse holder on an existing fuse that is switched with the ignition for the relay coil. This is what I did for our old trailer that had a 12V refrigerator heater as the newer F-150's can't handle the current on the Aux line due to a small 18 gauge wire.

[BobC]

I found two fused 30A aux terminals that don't have anything connected to them under the hood, right in front of the driver side dash. They're always on so I'll use a relay and a re-settable 20A breaker for each circuit (trailer brake and charging circuits) that I'll probably mount under the dash adjacent to the under-dash fuse panel.

[BobC]

For now, I just repurposed the PO's trailer brake line as a 12V Aux/charge line connected to the CB supply. The RVI toad charger I purchased has an inline 15A fuse and the CB supply also has a 15A fuse so I'll be OK load-wise. I test-towed my toad the other day and all went well but I haven't been on the freeway yet.

When I have more time, I'll run a second wire for the trailer brake from the controller and hook both the charge line and the trailer brake lines to the aux terminal(s) via relay(s) as I described in post #13. I doubt I'll ever tow a trailer with electric brakes but better to be ready for it than not since i have the controller.

[old_engineer]

Sounds like a good solution. Since you don't need it the brake wire should be fine. The important part is the wire used as the charge line be a large enough gauge to handle the current draw with minimal voltage drop. The brake wire is usually large enough for this.

[ADVNTUR]

2018 View 24 D. Would anyone be able to tell me what the amps would be on the power supply pin at the 7 pin connecter. Would like to supply power to charge the toad battery.

[TriGlider]

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