Seat Heaters

:Nissan Leaf
This upgrade describes how to install seat heaters in your 2011 Nissan Leaf.
For background, please see the DIY seat heaters forum thread.
The purpose of this page is to collect all of the information needed to install seat heaters, based on several cars that have already been upgraded in the SF BayLeafs group.
The Nissan Service Manual (You can purchase access to download it here) may be helpful for disassembly procedures, etc. Another approach is to find someone else (who has already done it) to help you.
Be sure to check out the Leaf seat heater installation photos from Bill (Electric4Me).
There are also photos from a recent SF BayLeaf three-car installation day and a series on mounting the Nissan Leaf Rear Seat Heater Switches from Steve (Lemketron).

Parts Needed

Heater Kit
Between two and eight pads, and one to four switches depending on how many seats
Heater kits can be purchased on ebay here (for two or four seats, with hi/low or dial switches):
Carbon Fiber Universal Heated TWO Seat Heater Kit on ebay ~ $83
Carbon Fiber Universal Heated FOUR Seat Heater Kit on ebay ~ $160
Seat heaters (TWO seats) with dial switches on ebay ~ $80
NOTE: SF BayLeaf folks have not yet installed a dial-switch version. In any case, these are probably recommended only for the front seats, as the round hi/low switches are most likely easier to install in the back of the center console.
Wire 14ga for +12V power supply
Considering wire gauge charts I would suggest using at least 18ga for all wiring, and preferably 16ga for everything except the primary (14ga) supply. This page also contains helpful suggestions for fuse and wire sizes. (–Steve)
Power Supply pig tail (1 run from fuse block, then split to each heater?)
Add-A-Circuit fuse taps are a clean way to get power out of the fuse block (rather than running an unfused wire to the center console and relying on the inline heater fuses)
Add-a-fuse for the Leaf. The one that I used is Littelfuse FHM200BP “mini Add A Circuit” available at any local auto parts store or on Amazon though the picture and description look incorrect on Amazon (read the reviews; need confirmation that this is correct). N.B. Must be a mini-fuse (aka ATM).
Bill’s fuse block solution, though
Arnold’s solution homemade power tap installed the additional fuses at the fuse block instead of the console.
Painter’s tape (to mask off plastic areas to keep from scratching)
Cable ties (4″ and 8″), about 15 of each minimum
Ring Connectors (14-16 ga, X2 for ground contacts)
Wire splicing materials, options include:
Insulated splices
Quick splices
solder and heat shrink tubing
Corrugated plastic tubing, aka split loom(optional, to “dress” the power and ground cable runs)
Marker Pen (for making labels for the cable runs Left/Right, and for drawing the cutting line on the heat pads)
Band Aids (if you touch the seats without gloves, you WILL need Band Aids)
Heated front seat switch:
Heated seat switch, from a single-seat heated seat kit from Sports Import Ltd.:
2012 Nissan LEAF heated seat switches part number 25500-1EA0A and 25500-1EA1A are available online from Nissan dealers and Factory Nissan Parts: These snap right into the console and create a nice high quality OEM look. They take a little bit of additional wiring but are likely worth the effort over using the cheaper switches that are often included with the heater kits.
Phil’s schematic (for wiring up the Nissan switches):
Mini Spade Lugs (for connecting the Nissan switches) on ebay or autotoys
Shrink Tubing (1/8″ for wiring the Nissan switches)
Molex Connectors (0.093″ Nissan Switches only)
6 connections (for wiring up switches, 1 set for each seat)
4 connections (for wiring up heater pads, 1 set for each seat)
T-splices 22 ga (for tapping into the illumination circuit)
Electrical Tape (for covering the T-taps with the spade lug inserted)
Wire
18 ga for grounding, current runs (red, black, white useful for ID)
22 ga for the illumination circuit
Other stuff?

Tools Needed

IMPORTANT: Work gloves to protect your hands — you will find a LOT of sharp edges all over the front seat frames (see “Band Aids” above). Tight-fitting leather gloves are highly recommended.

Carpet or clean tarps/cloths to put the seats on while installing heaters in the seats

10mm, 12mm and 16mm sockets, 3/8 drive ratchet, and extension

Torque wrench, 3/8 drive (to match 16 mm socket)

Plastic trim removal pry bar tools (Harbor Freight has a great kit for a few bucks)

Large ChannelLock (diagonal) cutters to clip “hog rings” inside the seat foam (seams)

Small diagonal cutters to trim wire ties (to replace “hog rings” in seat foam)

Scissors (to trim heater pads)

Needle nose pliers (to remove cut “hog ring” parts)

Regular pliers (help with T-tap connectors)

Assorted screwdrivers:

Jewelers flat screwdriver to release wire tie clips under the front seats

Long screwdriver helpful to unlatch seat fabric plastic interlocking bars)

Large-ish phillips screwdriver for center console screws

Torx T-15 screwdriver (to remove the center console screws)

Volt-ohmmeter (to test resistance of heaters after installation)

Knife

Electrical fish tape (to pull wiring harnesses under carpet from seats to center console)

Wire stripper/crimp tool

Drills

1/8″ for pilot hole in factory installed blank)

1/4″ for the hole saw bit

Hole Saw 3/4″ for the kit seat heater switches

Files for deburring the switch hole, and for the rear switches to creating a notch to accommodate the anti-rotate feature.

Molex Connector Crimp Tool (if using Molex connectors)

Flashlight (helps in fishing wires under the floor covering)

Installation Process

WARNING
The seats have air bags. Make sure you understand how to work with them safely. Consult the service manual for details.
EVDrive adds: “Don’t turn on your car with the seats out. If you do the airbags will shut off. Search the forum for airbag warning light and a quick no dealer fix/system reset is posted by another forum member. I was kicking myself all weekend thinking I could have broke the airbags and might have to pay through the nose to get them fixed.”
Need more details here, obviously, preferably with links to photos for critical parts.
We could include the high-level instructions below and/or link to new pages with detailed instructions and photos.
There are a couple of pictures that are probably worth highlighting, such as the positions of the connectors and cable clamps under the front seats, as well as the center console (and other plastic trim) prying locations.

Front Seats

Remove seats
Remove four bolts and lift the seat so the pin at the back is clear of its hole
Tilt seat back to release connectors
Make sure air bags are safe
Release cable tie holding seat wiring to the car. Here is picture what you will be trying to do somewhat blind.
Open seats up
How to undo the not so obvious black clip
Cut the hog rings on the bottoms
Install heaters
Cut pads to size
Seat backs shouldn’t need any active heating elements to be trimmed
Trim excess non-functional material from the cable end for the seat bottom
Pull tabs or at least create a starter for pulling the protective strip on the adhesive on the pads
Z fold to make it easier to insert the pad
Assemble seats
Use cable ties in place of hog rings
Re-install seats (after center console is reinstalled)

Rear Seats

Remove seats

Pull bottom (bench) cushion first: no bolts or screws, just lift up at the appropriate spot, the middle of the left and right seat bottom

Then remove seat backs: for each seat back, remove two bolts from the hinge bracket in the middle, and two nuts on the outboard side

Watch (or hang onto) the loose belt buckle when removing the seat back from the car

Open seat fabric

Bottom bench has four sets of hog rings

Install heaters

Poke a hole straight down in the bottom cushion for the pad power

Route power to the outside towards the door, exiting the seat back at the LATCH connector slot

Re-install seats

Center Console

Remove console (after front seats are removed)
Need detail picture showing where to use the pry tools
Need detail pictures showing screws, etc. to be removed in order to remove plastic trim panels
Run main power wire to fuse block
Note not all fuse block positions are switched! Use the ones closest to the front of the car.
Run wiring harnesses under carpet
Install front seat switches
Install rear seat switches (photos here: Rear Seat Heater Switches)
Replace console

Electrical

Electrical work can be done in stages. It is important to do the wiring harness runs from the seats to the switches while the center console and seats are out of the car. The power distribution run can be done at any time with everything in the car. The center console can be removed without removing the front seats to finish the wiring and switch installation. The start of a more complete instruction set appears here. This is a work in progress and will get updated as time permits.

Using the Nissan OEM switches

The wiring for the Nissan switches is different, you will need to modify the harness that comes with the kit. This requires advance work until we have a better set of procedures for it.

Retrofitting the Nissan OEM switches after you already installed the kit switches

If you didn’t have the Nissan switches when you installed your heaters and you wanted to retrofit them without having to take the seats back out to redo the wiring harness there is a solution. The switches can be used as direct substitute for the kit switches. Wire the Nissan switch per this diagram, shamelessly derived from Phil’s work.

When tapping for the lighting circuit, make sure you are far way enough from the connector allow for easy dressing of the cable. I tapped a little too close. It works but was not as neat as would have liked when I tried to dress it.

Pictures on the installed switches and showing off the illumination circuit in action

Power source:

Bring a source power from the fuse block, be sure to use a switched power source.
One such source is the “cigarette lighter” socket which is on its own 20-amp fuse.

Each seat consumes about 4.4A to 4.6A. An installed pair of seats draws around 9A. Plan your power feed accordingly.

Lighting:

Lighting for switches can be tapped into the P-R-N-D indicator from the console.

Ground

There is convenient grounding point (bolt) at the airbag computer in the console

Front switches

The switches barely fit into the blank fillers. You will want to install the blanks back into the cup holder/console before installing the switch.

You may want to cut a slot into the blanks to make for an easier fit

Rear switches

There is a metal bracket that you need to plan around for placement of the switches. Refer to Rear Seat Heater Switch location and measurement photos.