Wiring 04 Highlander to 7 pin Bargman connector

[Gary Little]

Is there a OEM wiring harness that will connect directly to the existing wiring in the left rear of the '04 Highlander and have either 6 or 7 wire leads or a 6 or 7 pin connector on the end that mounts to the hitch? I purchased one that has a 4 pin(3 female,1male) on the end but would like to have at least a 6 pin. Bargman and Hoppy make a adapter for this (4 pin to 7 pin) but I would rather not use another adapter.



thanks,
Gary little

[Brian B-P]

I don't know about the Highlander specifically, but for my '04 Sienna the Toyota adapter - and the others I found - all handle only lighting signals, and thus end in a four-pin connector. I use one of those 4-to7-pin adapters, to convert connectors and incorporate the brake control and charge wires.

I agree that more connections is undesireable. You can just cut off the 4-pin connector and connect the wires to a 7-pin socket with screw terminals. This still won't give you a moulded cable/connector assembly, but I don't think you're going to find that.

In general, if the auto manufacturer does not provide pre-wiring under the dash for a brake control, I would be surprised to find 7-pin wiring available for the back. Toyota properly pre-wires their trucks, but not the Sienna (and probably not the Highlander or Lexus RX, since all three are variations of the same vehicle).

By the way, in the Sienna the harness extends into both left and right tail light assemblies to tap into all required signals - not just one side. I don't know how painful this was to install, since the dealer put it in.

[Frederick L. Simson]

I use one of those 4-to7-pin adapters, to convert connectors and incorporate the brake control and charge wires.

I bought my Honda wiring harness from Camping World. It had the small square automotive plug that plugged into an open plug inside the left quarter panel. It it had a "brick" module in the center of the harness where the separate brake & turn signal paths are commingled, and ended in a 4-pin flat configuration, that is an automotive standard.

It plugs into the back of my 7-pin receptical that is mounted on my hitch receiver. The back of the receptical also has a short additional pigtail with the charge wire (black) ground wire (white) brake controller output (blue) and auxillary/back-up lamp wire (yellow) feeding the rest of the 7-pin socket.

[Craig Nold]

Gary,

The Highlander is not pre-wired for a break controller nor is there any seven pin connector offered as an option. A wiring harness with the flat four pin tail light connector comes packed in the glove box of highlanders that have the pre-towing package. If you want to charge the trailer battery or use trailer brakes, You will need to get a kit that has the remainder of the required parts.
The kit at the link below is one that I have used to wire several older Toyota trucks that didn't have a tow package.
Seven pin wiring kit

[Gary Little]

I don't know about the Highlander specifically, but for my '04 Sienna the Toyota adapter - and the others I found - all handle only lighting signals, and thus end in a four-pin connector. I use one of those 4-to7-pin adapters, to convert connectors and incorporate the brake control and charge wires.

I agree that more connections is undesireable. You can just cut off the 4-pin connector and connect the wires to a 7-pin socket with screw terminals. This still won't give you a moulded cable/connector assembly, but I don't think you're going to find that.

In general, if the auto manufacturer does not provide pre-wiring under the dash for a brake control, I would be surprised to find 7-pin wiring available for the back. Toyota properly pre-wires their trucks, but not the Sienna (and probably not the Highlander or Lexus RX, since all three are variations of the same vehicle).

By the way, in the Sienna the harness extends into both left and right tail light assemblies to tap into all required signals - not just one side. I don't know how painful this was to install, since the dealer put it in.

Thanks Brian,
Can you look to see if the dealer connected your "black charging" wire directly to your positive battery post in the Sienna? I have been told that I will have to do this and run the 10awg wire through a auto matic reset circuit breaker and then to the rear to my 6 or 7 pin connector. He also said to just cut the 4 wires on the flat connector and terminal connect them like you said. I have a "always hot" wire in the back(10 or 12awg)on the factory wiring harness. It seems to powers the convertor when the 20amp fuse is installed under the hood that came with the kit but I wonder if it would be best to do as mentioned above to isolate the 2 hot cicuits?

Thanks,
Gary

[Brian B-P]

...Can you look to see if the dealer connected your "black charging" wire directly to your positive battery post in the Sienna? I have been told that I will have to do this and run the 10awg wire through a auto matic reset circuit breaker and then to the rear to my 6 or 7 pin connector...

The Toyota dealer only installed the converter and wiring for the lights; I added the (black) charge line at the same time as the brake controller output (blue) and a dedicated ground wire (white).

[b]Yes, the 10-ga charge line is connected to the battery postive post through both a auto-reset circuit breaker. The line also goes through a relay; the relay is powered on by a tap into a circuit in the under-hood fuse box which is on only when the engine is running.

...He also said to just cut the 4 wires on the flat connector and terminal connect them like you said. I have a "always hot" wire in the back(10 or 12awg)on the factory wiring harness. It seems to powers the convertor when the 20amp fuse is installed under the hood that came with the kit but I wonder if it would be best to do as mentioned above to isolate the 2 hot cicuits?...

The power supply to the converter is required to power the trailer lights so they don't load down the tow vehicles light circuits. I do not believe that this has enough capacity to be used as the source to power the trailer (via the charge line), so [b]yes, I believe that an entirely separate (from the lighting supply) hot circuit for trailer charging is appropriate.

Since the Sienna is not pre-wired for trailer brakes, I had to run the blue wire for the brake controller output. While doing that, it was no big deal to run a black wire for charging, and to avoid any issues with grounding I put in another 10-ga wire (white) to the battery ground terminal as well. The biggest hassles associated with the charge line were mounting the breakers and relay, and finding a power source to control the relay. Then there's lying on the ground under the van finding places to route and attach the wires, but I don't mind doing that.

The brake controller also required fishing wires through the firewall to under the dash, connecting to the brake light switch, and mounting the controller, but that has nothing to do with the way it's connected at the back. It also has little relationship to the charge line, except that they both needed power connections with breakers, which I mounted on the same bracket.

[Gary Little]

The Toyota dealer only installed the converter and wiring for the lights; I added the (black) charge line at the same time as the brake controller output (blue) and a dedicated ground wire (white).

[b]Yes, the 10-ga charge line is connected to the battery postive post through both a auto-reset circuit breaker. The line also goes through a relay; the relay is powered on by a tap into a circuit in the under-hood fuse box which is on only when the engine is running.
The power supply to the converter is required to power the trailer lights so they don't load down the tow vehicles light circuits. I do not believe that this has enough capacity to be used as the source to power the trailer (via the charge line), so [b]yes, I believe that an entirely separate (from the lighting supply) hot circuit for trailer charging is appropriate.

Since the Sienna is not pre-wired for trailer brakes, I had to run the blue wire for the brake controller output. While doing that, it was no big deal to run a black wire for charging, and to avoid any issues with grounding I put in another 10-ga wire (white) to the battery ground terminal as well. The biggest hassles associated with the charge line were mounting the breakers and relay, and finding a power source to control the relay. Then there's lying on the ground under the van finding places to route and attach the wires, but I don't mind doing that.

The brake controller also required fishing wires through the firewall to under the dash, connecting to the brake light switch, and mounting the controller, but that has nothing to do with the way it's connected at the back. It also has little relationship to the charge line, except that they both needed power connections with breakers, which I mounted on the same bracket.

Thanks Brian,
I should be able to handle everything now. I probably want need brakes for the 13' Scamp but I will most likely go ahead and run the blue wire for later installation. I think I will try to find a 3 conductor cable to do this. It may make a neater job and easier.

Thanks again for the information.
Gary Little

[Brian B-P]

...I probably want need brakes for the 13' Scamp but I will most likely go ahead and run the blue wire for later installation...

I'm guessing you meant to type "I probably won't need brakes...". We've discussed the need for trailer brakes a few times, and I always vote for using the trailer brakes. Although the Highlander has up to 3500 lb of towing capacity, it is not uncommon for vehicles of that rating to require trailer brakes with trailers of 2000 lb or even less, and some states require them at quite low levels as well. Personally, I think adding almost half of the tow vehicle's weight without brakes is fundamentally a bad plan, even though I realize that many people (including myself with earlier trailers) have lots of experience getting away with it.

...I think I will try to find a 3 conductor cable to do this. It may make a neater job and easier...

I agree that it's a lot easier to run all the wires while you are in there. That wiring kit in Craig's link looks like a very tidy setup, assuming that it really has the right bits, including the right wires. It's not clear if it has a ground wire in nicely bundled harness, and I like knowing that the significant currents which could be flowing have a good path, especially with unibody construction (not a separate frame rail from hitch to battery ground like a typical pickup truck).

[Gary Little]

I'm guessing you meant to type "I probably won't need brakes...". We've discussed the need for trailer brakes a few times, and I always vote for using the trailer brakes. Although the Highlander has up to 3500 lb of towing capacity, it is not uncommon for vehicles of that rating to require trailer brakes with trailers of 2000 lb or even less, and some states require them at quite low levels as well. Personally, I think adding almost half of the tow vehicle's weight without brakes is fundamentally a bad plan, even though I realize that many people (including myself with earlier trailers) have lots of experience getting away with it.
I agree that it's a lot easier to run all the wires while you are in there. That wiring kit in Craig's link looks like a very tidy setup, assuming that it really has the right bits, including the right wires. It's not clear if it has a ground wire in nicely bundled harness, and I like knowing that the significant currents which could be flowing have a good path, especially with unibody construction (not a separate frame rail from hitch to battery ground like a typical pickup truck).

Sorry for the spelling. Yes, I meant "won't". The little scamp only weighs approx. 1000lbs. With your advise I will add brakes later when the axle needs replacing. It seems to pull good now but, it is 20 years old. Did you tap into the ignition fuse for the relay? Do you have any numbers or supplier for thr relay? Were all wires(blk,wht and blue)10awg or was the blue 12awg?

Thanks for all your help.
Gary

[Craig Nold]

The kit has everything needed for a tidy installation except the extra ground wire that Brian mentioned.

[Gary Little]

The kit has everything needed for a tidy installation except the extra ground wire that Brian mentioned.

Thanks Craig but I have already purchase the converter from my local Toyota dealer. I should have waited . Your route seems a lot easier and the cost will be a little less also. But, I don't see that the kit comes with a relay. Is it required?

Thanks,
Gary

[Brian B-P]

The little scamp only weighs approx. 1000lbs.

After seeing many discussions of trailer weight in this forum, I doubt the trailer actually weighs only 1000 lb (including the tongue weight) even empty, let alone loaded. Lots of people have been surprised when they visited a scale. Even 1000 lb is a very significant thing relative to the weight of most of our tow vehicles.

Gary, I'm glad to hear that you're planning for brakes.

[Brian B-P]

Did you tap into the ignition fuse for the relay?

Strangely, there is no fuse in the Sienna underhood box which simply goes on with the ignition switch. I used one which supplies the engine computer, but if I were to do this again, I would run an extra wire from my relay/breaker area through the firewall along with the brake controller wires, and tap into the under-dash fuse panel, where there would be a more appropriate source.

To tap in, I used a device (I got mine at Wal-Mart, following a description posted in another forum) which has two blades just like a fuse, two sockets on top to hold the fuse which should be plugged in there and an additional one, and a lead to supply the added circuit. No original wires are cut or tapped. while I used a different brand, it is like the Tapa-Circuit shown in the Go-RV online catalog.

Do you have any numbers or supplier for the relay

I used one of those enormous relays which looks like an old Ford starter solenoid. I bought it at an RV store, but they're really commonly available. For an example, see page 100 of the Go-RV online catalog, where it is called a "dual battery switch". I used the four-post style so I could run a ground wire, rather than grounding the control power through the relay mounting bracket (me and my ground wires again...) An actual starter solenoid (relay) is not suitable, because they are not intended to stay on continuously. Any continuous-duty relay of sufficient current rating would work, and if I were to do it again I would pick a more compact and lighter unit.

Were all wires(blk,wht and blue)10awg or was the blue 12awg?

I used 10 ga for both black and white. I couldn't readily find 10 ga blue-insulated wire, and it really isn't needed anyway. Each brake magnet uses about 3 or 4 amps at full force (they're very standard), and the Boler only has one axle (thus two brakes) so it only needs 6 to 8 amps. I believe that 12 ga is lots, and that's what I used; Cequent (the Prodigy controller manufacturer) specifies minimum sizes in their wiring instructions of 14 ga for up to two axles, and 12 ga for three or four axles. Within the trailer, the brake wiring is only 14 ga anyway, and with only one axle I believe I have suitable capacity. I used the recommended (by Cequent) 20 amp breaker to supply the brakes, and (I think) 30 amps for the charge line.

[Benny K]

Hi Gary, if you do a search for 12 volt relays you`ll find some cube relays,i.e. Bueler, in a 30/40 amp or higher capacity....these relays are about 1" square and you can get them with a mounting tab on them with spade connectors.....price on them looks to be about $2.....there are some on E-bay for $7.50 for a 10 pack in case you need a spare, LOL....I put a relay of this type on my son`s van for a RV battery and it`s been working fine for last couple summers.....I used a Ford starter type relay for charge control on a bus camper that I had for over 20 years without a problem.... Benny

[Craig Nold]

Gary you still need the converter and the flat four -pin connector. That takes care of the separate stop and turn light problem. The flat four-pin plug connects to a corresponding receptacle that is part of the kit. That way you can tow both four and seven pin trailers without an adaptor.
I did not use a relay to cut off the 12-volt power supply to the trailer. I just turn the frig off or pull the plug when I stop longer than it takes to fill the fuel tank. Some newer Toyota trucks come with that feature as part of the towing package.

[Gary Little]

Strangely, there is no fuse in the Sienna underhood box which simply goes on with the ignition switch. I used one which supplies the engine computer, but if I were to do this again, I would run an extra wire from my relay/breaker area through the firewall along with the brake controller wires, and tap into the under-dash fuse panel, where there would be a more appropriate source.

To tap in, I used a device (I got mine at Wal-Mart, following a description posted in another forum) which has two blades just like a fuse, two sockets on top to hold the fuse which should be plugged in there and an additional one, and a lead to supply the added circuit. No original wires are cut or tapped. while I used a different brand, it is like the Tapa-Circuit shown in the Go-RV online catalog.
I used one of those enormous relays which looks like an old Ford starter solenoid. I bought it at an RV store, but they're really commonly available. For an example, see page 100 of the Go-RV online catalog, where it is called a "dual battery switch". I used the four-post style so I could run a ground wire, rather than grounding the control power through the relay mounting bracket (me and my ground wires again...) An actual starter solenoid (relay) is not suitable, because they are not intended to stay on continuously. Any continuous-duty relay of sufficient current rating would work, and if I were to do it again I would pick a more compact and lighter unit.
I used 10 ga for both black and white. I couldn't readily find 10 ga blue-insulated wire, and it really isn't needed anyway. Each brake magnet uses about 3 or 4 amps at full force (they're very standard), and the Boler only has one axle (thus two brakes) so it only needs 6 to 8 amps. I believe that 12 ga is lots, and that's what I used; Cequent (the Prodigy controller manufacturer) specifies minimum sizes in their wiring instructions of 14 ga for up to two axles, and 12 ga for three or four axles. Within the trailer, the brake wiring is only 14 ga anyway, and with only one axle I believe I have suitable capacity. I used the recommended (by Cequent) 20 amp breaker to supply the brakes, and (I think) 30 amps for the charge line.

I completed my wiring this weekend. I think it turned out great . Thanks to Brian, Craig and Benny for all your imput. I love this forum.
Hopefully I will get the Scamp back Tuesday from Maaco. I did most of the prep work and they agreed to paint it for $400.00. I'll post some photo's of the wiring job.
Thanks to all again!
Gary Little

[Gary Little]

I completed my wiring this weekend. I think it turned out great . Thanks to Brian, Craig and Benny for all your imput. I love this forum.
Hopefully I will get the Scamp back Tuesday from Maaco. I did most of the prep work and they agreed to paint it for $400.00. I'll post some photo's of the wiring job.
Thanks to all again!
Gary Little

More photos

[Rocky R.]

This last weekend, I installed a 7-pin Bargman plug on our 2006 Toyota Highlander Hybrid. I used the same kit that Craig Nold used. Got that and a Valley Oddyssey brake controller from etrailer.com. Also installed a cell phone antenna, ham radio equipment and antenna and XM radio at the same time. We are looking at getting a fiberglass trailer sometime next year. We really like the Escape but at 17 feet we are not sure if the 3500 pound tow rating of our vehicle will handle it. We most likely will go with a 16 foot Casita or Scamp. I have attached a few photos of the work I did.

[Gary Little]

This last weekend, I installed a 7-pin Bargman plug on our 2006 Toyota Highlander Hybrid. I used the same kit that Craig Nold used. Got that and a Valley Oddyssey brake controller from etrailer.com. Also installed a cell phone antenna, ham radio equipment and antenna and XM radio at the same time. We are looking at getting a fiberglass trailer sometime next year. We really like the Escape but at 17 feet we are not sure if the 3500 pound tow rating of our vehicle will handle it. We most likely will go with a 16 foot Casita or Scamp. I have attached a few photos of the work I did.

That really looks neat Rocky. You did a fine job.You are probably right about the Escape. I looked at a nice 17' Casita this week but the tongue weight is around 335#. The Highland tongue wt. max. is 250# according to the dealer.

Thanks,
Gary