Lotus Elan Central
Installing Seat Heaters in your Elan

For those that are interested, I just purchased some seat heaters for my Elan. I was able to install the heating element for my driver's seat last night. The verdict ... It works great! Now I am able to drive with the top down in freezing conditions and be comfortable. BTW - I also have/use a wind blocker. So for those that are interested in the seat heaters check out this site ... As for the price, it cost me $106 a seat, which included shipping and handling. - Jamie

Additional seat heater links:


This material contained on this page is informational in nature only, and does not imply all knowledge needed to safely work on the electrical system of your Elan! It also does not include all instructions needed to properly install seat heaters into your seats. I will not warranty the contents nor will I take responsibility for your actions if you should attempt to work on your car based solely on these instructions. See DISCLAIMER. Failure to follow proper procedures can lead to vehicle fire and possible personal injury or death!

Jamie gave me the inspiration needed to install seat heater into my Elan. I know I already live in Southern California, where the weather is always great, but with the seat heaters I can be assured I can drive with the top down ANY day or night, except when it rains a few days a year!!

I purchased the seat heater kits from Katzkin as Jamie mentioned above. They were $88 each--I picked them up myself so there was no shipping for me. The kit is actually manufactured by Inalfa Sunroofs and seems to be very well made. Each kit comes with general instructions for the heating pad installation. The wiring has a built-in 10Amp fuse and fuse-holder and there are connectors that snap into each heating element so the seat is still easily removable. There is a lighted switch which has 3 positions: 'hi', 'off' and 'low.' The switch is finished in black plastic, similar to the color of the Elan's mirror control switch.

seat heating parts

The supplies needed for this installation are not that many, but it is an intricate and involved project. It requires a good time commitment and lots of swearing! The hard part is disassembling the seats to put in the heating element pads--the easy part is the wiring for the heaters! Plan to spend a full workday or 2 half days to get the whole project done!

With regard to wiring in the units, you only need an ignition-switched 'hot' and a 'ground.' It is certainly possible to "splice" the hot wire into another switched component on the car, but these heaters will draw a good current when in use. Thus, if you do this you will have to change the fuse of what you splice it into or you will likely end up blowing the fuse of the other circuit; and also with this set-up it would be possible for the other system to get damaged from using the higher fuse.

We are VERY lucky in this regard, however! I scrutinized the Elan electrical system manual and discovered gold! Lotus has placed wiring into all Elans for the factory security system, which no US Elans have installed. The electrical manual describes this system in detail as there are instructions for its post-production installation. Thus, there is an empty relay and fuse spot which can be easily accessed; and it just so happens it is even located in the speaker enclosure behind the left seat !! Even better, there is a wiring harness that comes alive with the placement of the relay and fuse with 4 connector wires that you can use for this project as I did.

[As an aside, these 4 wires would be perfect for use in the installation of about anything electrical. They consist of: a permanent 'hot', an ignition-switched 'hot', a 'ground', and a 'hot' lead from the headlamp/gauge lighting switch! ]

Pad Installation into Seats:

Remove Seats: [Whew, these seats weigh a whopping 38 pounds each!]

  • Remove the seats using a 17mm socket wrench. Hint: when you go to re-install them, the single larger spacer goes with the rear-outer bolt.

Disassemble seats: [HINT: seats are modular and not sided--this means you can change the seats so the left becomes the right and vice-versa if you wish, if the driver's is significantly more worn !!]

  • Remove bottom runners with 12mm and 13mm sockets--one bolt of each per side.
  • Remove black circular plastic adjustor wheel. There is a center plastic piece that is just held in by friction. To remove it just carefully pry it out. Underneath there is a 10mm bolt which retains the angle adjuster outer wheel to the seat. Be sure to get the little metal washer under it too!
  • Now you must remove the side plastic triangular piece. It is held in place by 2 small plastic push-pin-fasteners. To remove these you must carefully pry the center pin up and out of the fastener from underneath (use long thin flat screwdriver)--be careful pulling this center pin out as the plastic is soft! With the center pin removed you can then gently pry the rest of the fastener out. Now remove the plastic trim piece to reveal the 2 side screws beneath it.
  • Now you may separate the seat back from the seat bottom by removing two 13mm bolts on each side

Seat Back Pad Installation: [Do this before the bottom to get a sense of progress going as the bottom is much harder!]

  • Simply remove the ' tongue' from the ' groove' along the length of the bottom of the seatback to open up the cover.
  • Fell up the seat back with your hand to feel where the heating pad will go.
  • Cut a bit of the end off the pad to make the right size fit and place it under the seat cover up the seatback. I fastened the bottom edge to the seat back cushion with a dab of 3M adhesive spray and that's all.
  • Now close up the tongue and groove, with the connector coming out the proper side and you are done with the seat back

Seat Bottom Pad Installation:

bottom seat

1. Remove seat cover and cushion together from the underframe.

  • Use a flat screwdriver to pop open all the metal retaining clips on the bottom of seat bottom (there is one hiding in the back corner of each side too).
  • Pry open the small metal retaining O-clips from the rear sides of the bottom of the cover (save in place for later replacement).
  • Carefully pry the retaining metal sleeve slightly away from the edges of the seat cover all the way around the seat with a flat screwdriver.
  • Now you may remove the 'tongue' from the 'groove' all the way around the 4 sides of the bottom of the seat.
  • Carefully lift the seat cushion and cover upward from seat bottom frame and leave the frame and bottom flap behind

close view of bottom seat

2. Remove seat cover from cushion.

  • Carefully invert the leather seat cover upward and away from the cushion. Yes, it is still attached to the cushion!!
  • There are retaining wires which connect the cover to the cushion running WITHIN the cushion in roughly a checker-board (H-shaped) pattern. This is a tricky part--you must find the deeper of the wires (times 4) and cut the ends of them (buried slightly within the cushion) with wire cutters to remove by sliding out these deeper wires

seat cover and foam

  • Once all 4 deep wires are removed the seat cover will come free of the cushion.
  • Now remove all the little metal loop retainers from under seat cover as you will be reinstalling the seat cover without these!

3. Place heating pad and re-attach seat cover.

  • Place heating pad on cushion to determine where to place reinforcing black strips. See kit instructions. You will place the black strips on the pad where it will contact the cushion grooves.
  • Cut small holes in the black area per kit instructions for passage of your new retaining nylon zip-ties.
  • Put a plastic dowel in place of the wire elements in the 2 cross brace areas. You can leave the 2 side wires as-is.

heater pad

  • To slowly re-connect the cover to the cushion, run the large zip ties up from the bottom of the cushion, thru the cushion, thru the pad (in the reinforced area), over the plastic dowel, then back down thru the reinforced pad area, and back down thru the seat cushion to make a loop!
  • You will do this 3 times on each horizontal strip.
  • Place a new holder strip, supplied with the kit, on the bottom of the seat cushion so that the 3 zip ties will go thru it. Do this once for each row and then loosely connect the zip ties--you will not tighten them fully until the sides are reattached and you are sure everything is right!
  • Place large zip ties on the sides in the same fashion. I chose to do this as it was easier than reconnecting the little metal loops. The kit only supplies 6 zip ties per seat so I bought more--very cheap! You may keep the top wire here--you will not go thru the heating pad on the 2 sides. I put 2 of the wires I removed along the bottom to loop the side zip ties around them for support.
  • Zip all the ties to secure seat cover to cushion. They do not have to be monster tight, just tight enough to make the seat cover stay in place and look right to you!
  • Trim the far end of the heating pad to the length of the front edge of the seat.

Reassemble seats:

This is the reverse of disassembly, you can figure it out! This is where you could switch the seat sides if you wanted.

After replacing all the tongue-and-groove sides of the seat cover, use a rubber mallet (or gentle hammer) to close the gaps of the metal retainer lips around the bottom. Don't forget to re-do the 2 small metal O-clips on the sides of the seat bottom.

Relax, the hard part is over--get yourself a beer and your sanity back!


Before proceeding with the in-car wiring, you MUST disconnect the positive lead to car's battery--or risk an electrical fire like I encountered!!

Remove Seats and Center Console:

You already removed the seats, right?

  • Remove the left and right rear speaker housings by pulling forward and upward on them. They are only held in place by friction and by a little plastic socket on the inner side.

Remove center console:

  • Carefully pry up the edges of the mirror switch and the 2 window switches and lift them out of their spots.
  • Disconnect them from their wire harnesses.
  • Open lid to storage area in center console and remove the 2 screws on the bottom.
  • Lift out this tray and then remove the 2 larger screws beneath this tray.
  • Remove the 2 large screws beneath where the window switches sit.
  • Gently lift the console up and forward to remove it. You will need to have the parking brake max up and the shifter forward to help it clear on the way out. Be careful not to scratch anything as it is a tight fit.


Locate In-car Wiring and Wire-in Heaters:

The relay strip is located behind the left rear speaker housing (see first picture below). Mine looks different because it was moved a bit for placement of my subwoofer. You will see there are 2 relays in place on the left of the unit with an empty socket between them--this is the "phone relay" spot we will be using (see second picture below).

relay loction

relay strip

The relay you need for this is a Bosch Mini-relay (Lotus part # A100M6015F) which is identical to the one on the left end, which is the fuel-pump relay. For the final wiring you must obtain another identical relay and place it into the unused receptacle. However, you can simply "borrow" and use the fuel-pump relay while you install the heaters; but you will obviously not be able to drive the car until you replace the fuel-pump relay [BTW, this is the perfect anti-theft trick if you are leaving your car for more than a day or so!].

[FYI, I did check all my local auto parts stores, electronics stores, GM dealers, and a few other auto dealerships with NO success in finding the relay in question! I finally got one from R.D. Enterprises for $24 plus shipping--though they are cheaper from Dave Bean at $8.25. I still think this wiring is better than using an add-on relay (for only a few bucks) as the end result is nearly "factory."]

Now that the relay is in place, this completes the electrical connections to the white plastic connector at the middle of the strip. The four wires at this connector consist of: a permanent 'hot' (purple wire); an ignition-switched 'hot' (green wire), a 'ground' (black wire), and a 'hot' lead from the headlamp switch (orange wire). You will need to place a fuse into the fourth (or end) fuse slot to activate/fuse the green wire for your wiring!! I chose to place a 15Amp fuse here--I would rather have this fuse blow, which is readily accessible, than have one of the fuses blow on the individual heater wires, which end up buried within the center console upon reassembly!! Leave the third fuse spot blank as it is for the purple wire which we are not using. (FYI: I have not had any problems to date using the 15A fuse with both seat heater on 'hi' together)

Locate the WHITE plastic harness connector under the relay strip and remove the outer "dummy" cover from it (it took me a while to realize this is a blank connector attached to it so I wanted to point out its true name). this reveals the 4 'male' ends of the aforementioned wires.


Now you must simply twist the two red 'hot' wires from the heaters together and the two brown 'ground' wires together. I used "14-16AWG female bullet connector ends" (local hardware store) to plug the reds into the green and the browns into the black wire. I used this size as I could get the two red and brown wires twisted together into the end of this--the female end was a bit too large so I closed the size down with a pliers. I used empty "18-22AWG female bullet connector ends" to plug the other 2 male ends--these actually fit the white connector better, but I could not get the twisted wires from the heater side into the small end of this size connector for crimping, so I chose the other as stated above.

heater connections

That's it as far as wiring it to the car--I told you this was the easy part!! I did shorten (cut) the leads (red and brown wires) a bit from the harnesses as they were too long. You can now trial the system: plug it all together, replace the battery lead, and be sure it works properly!

Run Wires within Car:

Now you must run the wires from the wiring connector to the switch, wherever you put it. If you put the switches in the center console like I did, you can cut out a place for them with a new, sharp utility knife (did you just hear your mom's voice say, "don't cut yourself with that knife"?). If you do this be sure to error on the small side for the switch hole and then enlarge it slowly as needed. If the sides are too narrow it will "pinch" the switch and make it hard to toggle.

wire installed

Also when the switch holes are finalized, turn the console over and place spots of epoxy at all the corners of the cut console--this is how you keep it from cracking in the future due to the weakened area you created by cutting it !!

From the switches the wiring runs back to the respective speaker cover area to plug into your seats at the connector plugs. [HINT: use small nylon zip ties to hold the wires where you want]

seat heater switch

Now re-install the center console. I recommend putting a piece of tape on all the switch plugs so you can pull them up through their holes while you are replacing the center console down!! Be sure not to pinch any important wires and that it sits flat down.

Re-install the seats, plug the connectors together, and hide them under the speaker area covers while you replace them.

Now you are done!! Congratulate yourself by snuggling up with a cold beer or two in your new hot seats! But please don't drink and drive. ;-)

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