Tow vehicle has 4-way flat wiring and trailer has 7-way round

[gordon2]

Originally Posted by Alex Adams

So your going to have to explain to me where I have had to hack into the tow vehicle's wiring, All of the wires from the device connect to the junction box in the trailer. With a conventional brake controller, unless there is already a brake controller connector built into the wiring harness, you have to somehow splice a wire to the brake switch or the wire coming from the brake switch.

The AutowBrake still requires a 7-pin* trailer connection and that is where the modification (or hack as you call it) comes into play. If you install a AutowBrake on a trailer but do not have the 7-way* umbilical then the AutoBrake will not work.

If you already have a 7-way* connection that includes power for the brakes, then it is true that nothing additional needs to be done involving the tow vehicle's wiring. But for vehicles that do not come with a trailer connection, one is needed and that is a "hack into the wiring," power and lights.

So if you don't have the 7-way* then you need to install it. The AutowBrake controller still needs 12 volt power from the tow vehicle and a signal to know when the brakes are activated. As we both have stated, the AutowBrake controller does not need a direct connection to the brake pedal switch and that can be a big advantage.
---------------
* Note is possible to use a 4-pin however you would need to have your running lights on to have working trailer brakes, and that is likely to overload the circuit and is strongly ill-advised. In fact that is exactly the type of use mod that would void the vehicle warranty, so install a 7-pin that will provide sufficient power to the brakes, for any trailer with brakes.

[Alex Adams]

I get it now. I suspect, in the original poster's case, that a previous owner cut off the 6 wire stock connector and hacked on a 4 wire connector. That was the way my Boler came. They are 6 wire because the early Bolers didn't have backup lights. They also didn't have an onboard battery so everything 12 volt was run from the trailer being connected to the tow vehicle or from a converter if you were plugged into AC.

[Jon in AZ]

I’m not getting you. I believe some early Bolers and Scamps originally came with 4-pin wiring (no battery or brakes as originally built). The OP’s trailer has been upgraded to a 7-pin connector, probably because that’s what a previous owner’s vehicle had. It doesn’t mean all 7 wires are actually functional. It is common not to connect the back-up wire. Obviously the brake line is not being used either. Charge line may or may not be connected.

The vehicle has 4-pin, because that’s all Toyota offers on all their tow-rated passenger vehicles, even the 5000# rated Highlander. (Shame on you, Toyota. It’s one reason we opted for a Pilot instead, but that’s another story.) This Toyota can be made to work (with brakes). Others have done it!

Welcome to the joys of a 46 year old trailer!

[Alex Adams]

I have attached the quick start guide for Boler trailers. Look at the 12 volt wiring section.
BolerTravelTrailerQuickGuide_English.pdf

[Jon in AZ]

Thank you, Alex- that clarifies the original connector. But it’s anyone’s guess what’s there now. It’s had a least one major rehab in 2006. I’m guessing it’s a modern 7-pin. I wonder whether it has a modern converter/charger and battery.

When the OP adds brakes, they will switch it over to the current 7-pin standard, if it’s not already.

[Len S]

You don't need brakes on a 13 ft Boler. As for charging the battery with the 7 pin plug system; that is a good idea and would have the Toyota wired for that. I did my 2000 Mazda truck years ago , myself and worked well.

[Trixie]

I had the same dilemma with my 2020 Toyota Highlander. I opted for the OEM hitch with 4 pin harness. I like the look of it and how it is mounted in the bumper.
After that, I had a wiring shop add in the 4 to 7 pin adapter. It comes with a bracket to mount at the hitch. I had the same setup on my 2009 Highlander.

[boler girl]

Originally Posted by Jon in AZ

Thank you, Alex- that clarifies the original connector. But it’s anyone’s guess what’s there now. It’s had a least one major rehab in 2006. I’m guessing it’s a modern 7-pin. I wonder whether it has a modern converter/charger and battery.

When the OP adds brakes, they will switch it over to the current 7-pin standard, if it’s not already.

My 1974 boler was a fancy model that came with wet bath (removed by previous owner), 3-way fridge, propane stove and battery, but no brakes or back-up lights. It is currently wired to charge the battery, or so I was told by the previous owner - I must say that it has never properly recharged the battery, and we always end up using a trickle charger between trips to keep the battery at a decent level.

[boler girl]

Originally Posted by Trixie

I had the same dilemma with my 2020 Toyota Highlander. I opted for the OEM hitch with 4 pin harness. I like the look of it and how it is mounted in the bumper.
After that, I had a wiring shop add in the 4 to 7 pin adapter. It comes with a bracket to mount at the hitch. I had the same setup on my 2009 Highlander.

Thank you Trixie. I like the look of your hitch, but what I've learned from all of the responses so far is that some people have had bad experiences with poorly cut out bumpers, so I've chosen to go for an aftermarket hitch wired for a 7 pin. Once I know the boler's actual weight fully-loaded, I'll get brakes installed if the weight is over 1750# (or 50% of what my RAV4 Trail can tow).

[Len S]

Originally Posted by boler girl

My 1974 boler was a fancy model that came with wet bath (removed by previous owner), 3-way fridge, propane stove and battery, but no brakes or back-up lights. It is currently wired to charge the battery, or so I was told by the previous owner - I must say that it has never properly recharged the battery, and we always end up using a trickle charger between trips to keep the battery at a decent level.

It may have been wired for battery charging but if the wire was too small a gauge , the resistance of the smaller wire could have cut the voltage down to the point were it wouldn't charge. You need about 14 volts at the wire to the battery hookup with the vehicle running. Best way is run a wire from the vehicle battery to the trailer plug portion using about 8-10 gauge wire/ 8 preferred. Also mount a resettable fuse at the battery in case of any shorts happening. As for the 3-way fridge; the 12 volts are almost useless as the current draw is very high and MAY only work with the vehicle running. Most of the propane fridges today are propane and 110v ac. 12volt might be available as special order. I leave my propane running
all the time except when gassing up my vehicle but then check your provincial/state laws.

[Dbasdan]

I just experienced a similar situation. I bought a 2009 Rav4 with the 4cyl. Only 1500lbs. Tow capacity. I purchased a Trillium 1300 and needed to transport both from Phoenix to Northern California, about 800 miles. The Rav4 already had a hitch and 4 wire flat wiring. I made an adapter from the 7 wire connector on the trailer, to the 4 wire connector on the Rav4. This will not be my tow vehicle for anything other than the one trip. I just wanted lights on the trailer.

[Len S]

Originally Posted by boler girl

Thank you Trixie. I like the look of your hitch, but what I've learned from all of the responses so far is that some people have had bad experiences with poorly cut out bumpers, so I've chosen to go for an aftermarket hitch wired for a 7 pin. Once I know the boler's actual weight fully-loaded, I'll get brakes installed if the weight is over 1750# (or 50% of what my RAV4 Trail can tow).

Should be a sticker somewhere inside the trailer indicating a dry weight and a gross weight which should be no more than 1700 lbs , I believe.

[boler girl]

Len S, the sticker indicates that the gross vehicle weight is 1,350 lbs, but that's the pre-modification weight. I'm sure it's more than that now.

[Jon in AZ]

Originally Posted by Len S

You don't need brakes on a 13 ft Boler...

My Honda Pilot specifies trailer brakes over 1000# trailer weight. That’s pretty common with small and mid-size crossovers. A few states have a low threshold for trailer brakes, too.

[boler girl]

Originally Posted by Len S

It may have been wired for battery charging but if the wire was too small a gauge , the resistance of the smaller wire could have cut the voltage down to the point were it wouldn't charge. You need about 14 volts at the wire to the battery hookup with the vehicle running. Best way is run a wire from the vehicle battery to the trailer plug portion using about 8-10 gauge wire/ 8 preferred. Also mount a resettable fuse at the battery in case of any shorts happening. As for the 3-way fridge; the 12 volts are almost useless as the current draw is very high and MAY only work with the vehicle running. Most of the propane fridges today are propane and 110v ac. 12volt might be available as special order. I leave my propane running
all the time except when gassing up my vehicle but then check your provincial/state laws.

With my lack of knowledge, I doubt I'd be able to conduct this test properly.

A few years ago, I discovered that the fridge was pulling too much power when I ended up with a dead car battery. Now, we travel with an ice pack in the freezer, and use propane or electricity once at destination.

[Glenn Baglo]

When I had my RAV4 wired, I specified #10 gauge. Cost me an extra $25.

[Len S]

Originally Posted by Jon in AZ

My Honda Pilot specifies trailer brakes over 1000# trailer weight. That’s pretty common with small and mid-size crossovers. A few states have a low threshold for trailer brakes, too.

Here in BC,Canada I believe it is 2500 lbs loaded ( gross weight) but that may have changed . The laws were your towing vehicle is registered/licensed is what
you normally would be required to go with.
Now is that what is recommended by Toyota or what is require by law ? Sometimes, what one person reads and what one person understands can be different . There is also the combined vehicle and trailer weight to consider and if towing is allowed they will specify that in their owners booklet plus it should be stickered on the door post on the drivers side.

[Len S]

Originally Posted by boler girl

With my lack of knowledge, I doubt I'd be able to conduct this test properly.

A few years ago, I discovered that the fridge was pulling too much power when I ended up with a dead car battery. Now, we travel with an ice pack in the freezer, and use propane or electricity once at destination.

If you ended up with a dead battery while driving ; I would suspect that you may have an issue with the charging system on the vehicle. If the fridge was still hooked up to the 12v and not propane when parked ; then that was my point of never using 12v. The current draw is somewhere around 14-16 amps. I always run my fridge on propane when parked and on the road ; except on the ferries or were prohibited . when plugged into 110v it auto switches to 110v from propane.

[Len S]

Originally Posted by Jon in AZ

My Honda Pilot specifies trailer brakes over 1000# trailer weight. That’s pretty common with small and mid-size crossovers. A few states have a low threshold for trailer brakes, too.

For the most part the Honda pilot is not a light car with a curb weight of a bit over 4000 pounds and if they call for brakes on a trailer over 1000 pounds that tells me that they are concerned with liability with their braking system; ie brake fade and let me tell you it can be real scary . I have experienced it and it's no fun . Scared the crap out of me

When I bought my new 2016 Ford F-150 the sales person sold me on buying the factory electric brake controller for the same price as one of the better aftermarket ones. It was installed and programmed to the truck before delivery so I got the same warrantee as the rest of the truck.
It was worth every penny and then some. When towing down hill I gently tap the brakes and it downshifts and uses the engine compression to keep
better control of the driven speed. When the downhill grade is such that the compression won't hold it then you have to assist with braking. I could tell after the first year of use by the brakes looking like the truck just rolled off the showroom floor. Have never experienced any brake fade with this one.

[boler girl]

Civilguy referred me to this link for Canadian towing laws
https://www.rvda.ca/ProvBrakeReqts.asp

BC: Gross trailer weight of 1,400 kg (3,080 Ibs) or less – Brakes are required if the trailer and its load weigh more than 50% of the licensed weight of the vehicle towing it.

So now I realize that if the gross vehicular weight of my TV is 4704 lbs, I actually don't have to put on brakes if the loaded trailer weighs up to 2352 lbs. At first read I thought it was 50% of what the TV could tow.