Automotive Wiring Question

[Ventucky Red]

I need to install the trailer light converter on our 2018 Toyota Sienna Van... your basic 4 pole flat trailer light plug... I got the harness from Toyota and like the others it requires a hot connection to the car's battery... which to run is going to be a real pain in the keyster.

In the back of the van there is a 20 amp cigarette style plug that has a dedicated hot wire.... the light next to it has it own as well. I am figuring in place of running the hot all the way to the front for a battery connection I would just tap into the existing 20 amp line as this is right behind the tail light where I need to do the un-plug and plug thing for the trailer light harness... meaning I will be in there anyway. I don't foresee myself using that outlet now or in the future anyway..

Here is my concern... I have been told the reason they have these is to take the load off the existing light circuits and providing dedicated of power for the trailer lights. How much power can your basic trailer (catamaran boat) use to light LED trailer lights? Of course if I go this route there will be an in-line fuse with a less rated fuse as an added precaution..

Anyone here familiar with these things that can give me some guidance?

Thanks

Ventucky

 

[flhrci]

Can't help now but in the future I will advise buying a vehicle with a trailer kit installed.

 

[asicer]

In the back of the van there is a 20 amp cigarette style plug that has a dedicated hot wire....
How much power can your basic trailer (catamaran boat) use to light LED trailer lights?

Unless you got the cheap ones, lot less than 20A.

 

[geezer]

First, what size fuse did Toyota recommend connecting to? If less than 20 amps, put in an inline fuse of the proper size.

Tapping the lighter circuit is the way to go, and more than enough current for trailer lights. Much safer than running wire to the front of the vehicle.

Leave the wire on the lighter outlet, for use in the future, having two wires on it is no problem, and that outlet is very handy.

 

[Matthew]

My Outback has a dedicated trailer light connection in the wiring harness. You plug in a 4-flat module that includes a 10A fuse. I can't help with anything else.

4-flat will have ground, lights, left turn signal/brakes, and right turn signal/brakes. No power directly from the battery is needed. In many cases people will splice directly into the tail-light signals of the car.

Edit: D’oh, yeah, the converter module probably does need 12V for itself. But still, the module I have uses a 10A fuse.

 

[Ventucky Red]

Can't help now but in the future I will advise buying a vehicle with a trailer kit installed.

For what I paid for the van I am not complaining... It had the hitch, I guess for bike racks and such, but no light hook up... they gave me a discount on the harness, but wanted $850 to install it... said it was an all day job.

First, what size fuse did Toyota recommend connecting to? If less than 20 amps, put in an inline fuse of the proper size.

Tapping the lighter circuit is the way to go, and more than enough current for trailer lights. Much safer than running wire to the front of the vehicle.

Leave the wire on the lighter outlet, for use in the future, having two wires on it is no problem, and that outlet is very handy.

Toyota is recommending 20 amps... my trailer light's are LED so I know they are less than that..

 

[Matthew]

My go to for any trailer wiring or accessories is etrailer.

They even have installation videos.

https://www.etrailer.com/t1-2018_Toyota_Sienna.htm

Here's one install video:
https://www.etrailer.com/Custom-Fit...hicleID=201830385#exp-productdetails=.reviews

https://images.etrailer.com/static/...trailer-wiring-2018-toyota-sienna-118648.webm

You can call or email, they are pretty good at responding to questions.

edit:

After looking at the video, I can see why the dealer said it would be an all day job. Running the power to the battery doesn't look like a lot of fun. Rather than a single plug, you need to pull out all the tail and brake lights, plug in t-connectors at all of them and then reinstall, then run power all the way up. Yeah, tap into something closer and be done with it.

 

[RJM62]

If you're using LED lights on the trailer, it will be fine. If you're using LED lamps with incandescent markers (a too-common arrangement), you'll also be fine.

Even with incandescent lamps, the total amperage draw of the taillights and the marker lights should be less than 7 amps (intermittently) when the high filaments are lit. 1157 lamps draw about 2.1 amps when both filaments are lit. The side lamps in the taillight housings and marker lamps are 0.6 amps each. So if everything is working exactly to spec, total draw would be 6.6 amps.

I'd wire it into the accessory receptacle with a 10-amp fuse between that circuit and the power to the trailer adapter. That should cover you even if you occasionally tow an all-incandescent trailer.

Rich

 

[Ventucky Red]

My go to for any trailer wiring or accessories is etrailer.

After looking at the video, I can see why the dealer said it would be an all day job. Running the power to the battery doesn't look like a lot of fun. Rather than a single plug, you need to pull out all the tail and brake lights, plug in t-connectors at all of them and then reinstall, then run power all the way up. Yeah, tap into something closer and be done with it.

I have used eTrailer a lot in the past..they do a good job

I was able to convince the parts guy at the Toyota counter to print out the installation instructions for me... all 26 pages of it... But they are pretty detailed with lots of pictures.

 

[Matthew]

I was able to convince the parts guy at the Toyota counter to print out the installation instructions for me... all 26 pages of it... But they are pretty detailed with lots of pictures.

And they'll generally have a very good step by step set of instructions. Have fun!

 

[manac]

You probably don’t need to hook up the 12V always hot for your boat trailer. The always on is for interior lights or loading lights you might want on when the tow vehicle is not running.

 

[flhrci]

For what I paid for the van I am not complaining... It had the hitch, I guess for bike racks and such, but no light hook up... they gave me a discount on the harness, but wanted $850 to install it... said it was an all day job.

Pricey!!!!!

 

[Ventucky Red]

You probably don’t need to hook up the 12V always hot for your boat trailer. The always on is for interior lights or loading lights you might want on when the tow vehicle is not running.

I found why we need to do this now... the constant power is there to power the trailer lights and separate it from the car's electrical system... with all the computer as such this make for a safer instaltion... The current coming form the car lights to the adapter box are triggering a switch for the specific operations...

And they'll generally have a very good step by step set of instructions. Have fun!

They are very detailed and written to I would say a sixth grade reading level.... At least I be able to listen to the game this Sunday...

Pricey!!!!!

Yes... the installation was pricey, the harness itself not much more that the aftermarket stuff... the van... I am still ahead of the curve after 18 months of ownership...

 

[Matthew]

I found why we need to do this now... the constant power is there to power the trailer lights and separate it from the car's electrical system... with all the computer as such this make for a safer instaltion... The current coming form the car lights to the adapter box are triggering a switch for the specific operations...



They are very detailed and written to I would say a sixth grade reading level.... At least I be able to listen to the game this Sunday...



Yes... the installation was pricey, the harness itself not much more that the aftermarket stuff... the van... I am still ahead of the curve after 18 months of ownership...

You’ll probably have an option of where to hang the connector. The OEM instructions will show how to run it through the floor and then attach (probably zip tie) to the hitch. An option is to leave it coiled up and stowed somewhere in the trunk area. When you need it you pull out as much as you need and close the lift gate on it. The weatherstripping will protect it from getting pinched as long as you avoid the latch. The second option keeps the connector out of the elements for the 99% of the time it won’t be used.

 

[Sac Arrow]

I don't know the answer to that, but want to know more about that catamaran...

 

[Ventucky Red]

I don't know the answer to that, but want to know more about that catamaran...

Prindle 18-2.... there is very nice NACRA 5.8 in Seattle I may acquire... hence getting the lighting harness rigged up...

This is my last 5.8..... for the Santa Barabara Channel... there is no better boat..

 

[RJM62]

I found why we need to do this now... the constant power is there to power the trailer lights and separate it from the car's electrical system... with all the computer as such this make for a safer instaltion... The current coming form the car lights to the adapter box are triggering a switch for the specific operations...

Yes, the main purpose of the adapter module is to isolate the trailer lighting from the vehicle lighting. That's why I always use them even if the trailer has LED lamps. It used to be a short in the trailer lighting (a common occurrence) would burn out a $0.30 fuse. Nowadays, it could burn out a $300.00 BCM. The module is a smart investment.

On a related note, I recommend you wrap any wires you run in wire loom. Also use some sort of electrical contact grease on, well, the electrical contacts. It hasn't dawned on anyone to make those things corrosion-proof.

Rich

 

[Sac Arrow]

Prindle 18-2.... there is very nice NACRA 5.8 in Seattle I may acquire... hence getting the lighting harness rigged up...

This is my last 5.8..... for the Santa Barabara Channel... there is no better boat..

That is one sweet looking Prindle. In my high school days, we had a Hobie 16. It was lots of fun. I've logged my share of hours in sailboats growing up.

 

[flhrci]

@Ventucky Red That's dangerous!

Looks nice!

 

[Ventucky Red]

Yes, the main purpose of the adapter module is to isolate the trailer lighting from the vehicle lighting. That's why I always use them even if the trailer has LED lamps. It used to be a short in the trailer lighting (a common occurrence) would burn out a $0.30 fuse. Nowadays, it could burn out a $300.00 BCM. The module is a smart investment.

On a related note, I recommend you wrap any wires you run in wire loom. Also use some sort of electrical contact grease on, well, the electrical contacts. It hasn't dawned on anyone to make those things corrosion-proof.

Rich

Thanks Rich... the wires are wrapped.. guess this is why Toyota charges a little more... and I am a big believer in dielectric grease.