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 ... http://www.Katzkin.com  As for the price, it cost me $106 a seat, which included shipping and handling. 

--Jamie


Additional seat heater links:

http://www.aaaconvertible.com/seats.html 

http://www.checkcorp.com/ 

 http://www.flash.net/~duetto/seatheaters.htm 

http://www.bergwerks.com/seat_heat.jsp  

http://shop.store.yahoo.com/gomiata/gomseatheat.html 

http://www.nwautoleather.com/nwautoleather/seat-heaters.html 

http://store.yahoo.com/4at-last/seatheater.html 

http://www.miata.net/garage/duetto_seat.html 

http://www.rostra.com/pdf/seatheater-install.pdf 


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.

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!]

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 !!]

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

Seat Bottom Pad Installation:

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

2.  Remove seat cover from cushion.

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

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!


Wiring:

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:

Locate In-car Wiring and Wire-in Heaters:

The relay strip is located behind the left rear speaker housing (see picture at right).  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 picture at left).  

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 (see links) for $24 plus shipping--though they are cheaper from Dave Bean at $8.25 (see links).  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.

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.

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]

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.  ;-)


I hope you enjoyed this write-up! Please let me know if it was helpful to you.

Happy Elaning, Doug