Model S Trailer Hitch Installation

[DayTrippin]

The cover should help quite a bit. It least it is a fairly low profile trailer.

 

[Jasper7821]

The cover should help quite a bit. It least it is a fairly low profile trailer.

It would be great if the cover saved 100 watts, but that seems kinda high. We'll see what happens.

 

[jjvan]

This past week I installed the new 4000 lbs rated ecohitch on my model s. It took a few hours for the hitch and another few hours for the wiring. Here are the pics of the hitch installation:

 

[jjvan]

For the wiring, instead of using the expensive tekonsha wiring kit I used a $10 four relay opto isolation board from amazon that was suggested by another TMC member here.
I powered it from the power liftgate 12V which is fused and is available from the power liftgate module on the right side of the trunk. This saves having to run a wire all the way to the 12v battery.
I tapped the turn and the tail wires from rear body lights on each side and those are fed to the triggers of the relay module which then powers the 4 wire trailer cable.
If you combine the two tail wires from each side with a relay you ensure that the tail lights only turn on when both tail wires are on. This prevents the tail lights from turning on when turning right or left. This was suggested by another TMC member here.

Here’s a photo of the relay wired up before I wrapped it up and tucked it behind the right side carpet:

Here are the wire colours that I tapped into for a 2015 85D which I found on a Tesla circuit diagram here:

Liftgate module on right side of trunk:
12V+: Red - Gray
12V-: Black

Rear light on right side of trunk:
Right Turn: Tan-Black
Right Tail: Tan-Dark Blue

Left light on left side of trunk:
Left Turn: Red
Left Tail: Violet-Gray

So far the setup works great! However the relays make a clicking noise when the turn signals are on. I will make a modification to add a manual switch to shutoff the relay board when I'm not using the trailer.

 

[DayTrippin]

Was the wiring done with the bumper cover on, or did you have to have it off to access some of the wires?

I ask because I just may want the hitch on for a bike rack and then maybe later may decide to tow if my 3 doesn't work out as I hope. So I'd want to know if I can install the hitch first and then not have to pull anything apart to wire the trailer wiring later.

 

[jjvan]

Was the wiring done with the bumper cover on, or did you have to have it off to access some of the wires?

I ask because I just may want the hitch on for a bike rack and then maybe later may decide to tow if my 3 doesn't work out as I hope. So I'd want to know if I can install the hitch first and then not have to pull anything apart to wire the trailer wiring later.

I did the wiring after I put the bumper and exterior trim back together but I left the interior trunk trim pieces off to access the wiring. Those trim pieces are pretty easy to take off again and do the wiring later if needed.

 

[jjvan]

Here is a pic of the lift gate module on the right side of the trunk where I tapped the 12v+ and 12v-.

 

[Jasper7821]

Wow, that hitch is much beefier. Mine is still in the box.
Pulling the boat 150 miles to the lake most weekends was just going to be too stressful on calculations and having to stop twice for 40-50 minutes.
I absolutely I love my Tesla but I ended up trading it in for a Porsche Cayenne diesel. I’m paying for fuel now, but I don’t have to stress and I am not limited to where I can take the boat. I want to go to Lake Havasu a few times and there’s no way I’d do that trip with the Tesla and all the stops I’d have to make.
This summer is all about getting out of the 115 degree heat and being on the lake most every weekend. I had to let the Tesla go.

Took the boat to the lake over the weekend and getting 23mpg at 65-70mph and it gets 34mpg without the boat at 80mph.

I’ll be back with a Tesla when my Cybertruck is ready.
I have my Zero motorcycle, so I’m still partially electric .

Thank you everyone for all the advice.

 

[FlatSix911]

Wow, that hitch is much beefier. Mine is still in the box.
Pulling the boat 150 miles to the lake most weekends was just going to be too stressful on calculations and having to stop twice for 40-50 minutes.
I absolutely I love my Tesla but I ended up trading it in for a Porsche Cayenne diesel. I’m paying for fuel now, but I don’t have to stress and I am not limited to where I can take the boat. I want to go to Lake Havasu a few times and there’s no way I’d do that trip with the Tesla and all the stops I’d have to make.
This summer is all about getting out of the 115 degree heat and being on the lake most every weekend. I had to let the Tesla go.

Took the boat to the lake over the weekend and getting 23mpg at 65-70mph and it gets 34mpg without the boat at 80mph.

I’ll be back with a Tesla when my Cybertruck is ready.
I have my Zero motorcycle, so I’m still partially electric .

Thank you everyone for all the advice.

View attachment 811530

Different strokes for different folks.

 

[DayTrippin]

Wow, that hitch is much beefier. Mine is still in the box.
Pulling the boat 150 miles to the lake most weekends was just going to be too stressful on calculations and having to stop twice for 40-50 minutes.
I absolutely I love my Tesla but I ended up trading it in for a Porsche Cayenne diesel. I’m paying for fuel now, but I don’t have to stress and I am not limited to where I can take the boat. I want to go to Lake Havasu a few times and there’s no way I’d do that trip with the Tesla and all the stops I’d have to make.
This summer is all about getting out of the 115 degree heat and being on the lake most every weekend. I had to let the Tesla go.

Took the boat to the lake over the weekend and getting 23mpg at 65-70mph and it gets 34mpg without the boat at 80mph.

I’ll be back with a Tesla when my Cybertruck is ready.
I have my Zero motorcycle, so I’m still partially electric .

Thank you everyone for all the advice.

Good luck with the Cayenne. The person who bought my Y had a Cayenne. He decided to bail out when the repairs were costing him a fortune for it. I think he spent 15k in repairs on it last year. I think once it had about 70-80k miles the reliability just plummeted.

A close friend of mine loves his Cayenne Diesel but again the repair costs are getting up there. He loves the range of it but in the last 2 years it has definitely been less reliable. He has a Y on order as well.

A worthwhile alternative for a decent tow truck with good mileage is a Ram Ecodiesel. I towed all over the US with mine and even with a very tall boxy trailer behind it got in the high teens towing at 75 mph. Unloaded I could easily go 500-600 miles on a tank of diesel and getting over 30 mph.

Enjoy the new ride and ditch it when the miles get up there.

 

[Jasper7821]

Good luck with the Cayenne. The person who bought my Y had a Cayenne. He decided to bail out when the repairs were costing him a fortune for it. I think he spent 15k in repairs on it last year. I think once it had about 70-80k miles the reliability just plummeted.

A close friend of mine loves his Cayenne Diesel but again the repair costs are getting up there. He loves the range of it but in the last 2 years it has definitely been less reliable. He has a Y on order as well.

A worthwhile alternative for a decent tow truck with good mileage is a Ram Ecodiesel. I towed all over the US with mine and even with a very tall boxy trailer behind it got in the high teens towing at 75 mph. Unloaded I could easily go 500-600 miles on a tank of diesel and getting over 30 mph.

Enjoy the new ride and ditch it when the miles get up there.

Thank you, the miles are already up there. Bought it last week with 98k and already have 99k. It was a one owner car and taken to the dealer for everything.
I would’ve bought a Y, but just too expensive right now.
I just needed something now to pull the boat 300 miles almost every weekend and with over 700 mile range and 34mpg no towing or 23mpg pulling the boat, I traded thee guy my Tesla and I got 7k back and the car.

I’ve always been a Porsche lover and had several different ones and did all the work myself. Hopefully this one will be good for a while.
I do also have a Lightning reservation and whichever comes up first, that or the Cybertruck I’ll get and sell this car.

 

[jjvan]

Thank you, the miles are already up there. Bought it last week with 98k and already have 99k. It was a one owner car and taken to the dealer for everything.
I would’ve bought a Y, but just too expensive right now.
I just needed something now to pull the boat 300 miles almost every weekend and with over 700 mile range and 34mpg no towing or 23mpg pulling the boat, I traded thee guy my Tesla and I got 7k back and the car.

I’ve always been a Porsche lover and had several different ones and did all the work myself. Hopefully this one will be good for a while.
I do also have a Lightning reservation and whichever comes up first, that or the Cybertruck I’ll get and sell this car.

Oh too bad the Model S wasn’t working for you.

My towing trips are much less distance than yours and I am loving towing with my Model S. I towed my 4000 lb sailboat about 50 km (30 miles) with no trouble at all. It climbs hills so much better than my v8 F150 truck and with no roaring engine sound.

It does come with a hefty range hit though. It used about 3x the power. My sailboat is the opposite of aerodynamic.

I towed the boat in and out of the water on a steep boat ramp yesterday and had no issues. Visibility was good and the backup camera is great to line up the hitch to the trailer.

For peace of mind I did use a length of 2x4 to wedge the brake pedal down while on the ramp to ensure that all 4 wheels are locked while I was dealing with the boat. Otherwise you are relying only on the rear parking brake. I recommend others do the same.

 

[jjvan]

The best way to get better range is to drive slower especially while towing a boat that has significant wind drag like mine. If you are ever worried that you won't reach the next supercharger, move to the slow lane and reduce speed.

 

[Jasper7821]

The best way to get better range is to drive slower especially while towing a boat that has significant wind drag like mine. If you are ever worried that you won't reach the next supercharger, move to the slow lane and reduce speed.

View attachment 811863

Driving the boat home 160 miles took almost two extra hours. And the last 50 miles I was driving 50-55 in a 75mph zone (everyone does 90 anyways) just to keep the car saying I’ll get home with 4% if I remember correctly.
The closest decent lake is 150 miles away, and it was just too complicated calculated getting there and back for the day. And with 3 other passengers it would’ve been just too inconvenient.
I will go back to electric when one of my reservations is ready.
Until then, I’m happy with the Cayenne diesel.

 

[Jasper7821]

Oh too bad the Model S wasn’t working for you.

My towing trips are much less distance than yours and I am loving towing with my Model S. I towed my 4000 lb sailboat about 50 km (30 miles) with no trouble at all. It climbs hills so much better than my v8 F150 truck and with no roaring engine sound.

It does come with a hefty range hit though. It used about 3x the power. My sailboat is the opposite of aerodynamic.

I towed the boat in and out of the water on a steep boat ramp yesterday and had no issues. Visibility was good and the backup camera is great to line up the hitch to the trailer.

For peace of mind I did use a length of 2x4 to wedge the brake pedal down while on the ramp to ensure that all 4 wheels are locked while I was dealing with the boat. Otherwise you are relying only on the rear parking brake. I recommend others do the same.

My Tesla did tow the boat with total ease and it was great. If the lake was 50 miles away, I totally would’ve kept the Tesla and make it work. But 150-175 miles to the closest decent lakes was just too inconvenient for me.

 

[jjvan]

Driving the boat home 160 miles took almost two extra hours. And the last 50 miles I was driving 50-55 in a 75mph zone (everyone does 90 anyways) just to keep the car saying I’ll get home with 4% if I remember correctly.
The closest decent lake is 150 miles away, and it was just too complicated calculated getting there and back for the day. And with 3 other passengers it would’ve been just too inconvenient.
I will go back to electric when one of my reservations is ready.
Until then, I’m happy with the Cayenne diesel.

Every EV is going to take a massive range hit when towing because EVs use all the design tricks to be extra aerodynamic and efficient. You throw all that efficiently out the window when you tow something like a boat. This will be true also for other EVs including the Cybertruck.

The solution to make long distance towing work is fast charging speeds and frequent access to charging stations. Charging speeds are pretty good when your state of charge is lower. For example, if you can always charge from 10% to 50% and then drive 50 miles to the next supercharger and charge from 10% to 50% again, it wouldn't be so bad. If you have to charge all the way to 95% at a charger it will be a long while. Access to charging at your destination also saves a lot of time. When I do any road trip I pretty much make sure that I have access to overnight charging at my destination to allow the next leg of the trip to start at 100%. I realize that there are still not enough chargers around to make this convenient for everyone.

 

[Jasper7821]

Every EV is going to take a massive range hit when towing because EVs use all the design tricks to be extra aerodynamic and efficient. You throw all that efficiently out the window when you tow something like a boat. This will be true also for other EVs including the Cybertruck.

The solution to make long distance towing work is fast charging speeds and frequent access to charging stations. Charging speeds are pretty good when your state of charge is lower. For example, if you can always charge from 10% to 50% and then drive 50 miles to the next supercharger and charge from 10% to 50% again, it wouldn't be so bad. If you have to charge all the way to 95% at a charger it will be a long while. Access to charging at your destination also saves a lot of time. When I do any road trip I pretty much make sure that I have access to overnight charging at my destination to allow the next leg of the trip to start at 100%. I realize that there are still not enough chargers around to make this convenient for everyone.

Unfortunately, the lake is almost 130 miles away and no Superchargers along the way.

 

[dmwahl]

The best way to get better range is to drive slower especially while towing a boat that has significant wind drag like mine. If you are ever worried that you won't reach the next supercharger, move to the slow lane and reduce speed.

View attachment 811863

@jjvan Do you have trailer brakes?

 

[jjvan]

@jjvan Do you have trailer brakes?

Yes the trailer has brakes.

 

[dmwahl]

One question I've had is if any of the model s owners who tow have suggestions for backing the trailer. The car goes into park when I do what I normally do, which is lift off the seat and turn most of my body around. I find it helps make the backing up more intuitive vs trying to use the mirrors and camera. Can the shift to park when my butt lifts off the seat be disabled somehow?

Also figured I'd share a picture. I liked the combination of the blue sky, red car, and green plant life. Also always fun are the reactions from people Hopefully will show up now when anyone searches google for "tesla model s towing boat" or similar.