Adding Heated Seats
Adding Heated Seats
Step 1 of adding the cold weather package to my 08 FSXT.
So the 08 Forester Sports is probably the only Forester that doesn't come wired for seat heaters. Here's how I did my install using factory wiring.
First, I gained inspiration from this thread:
http://www.subaruforester.org/vbulletin/f77/how-heated-seat-repair-install-62332/
In that thread he pulled his entire system out of a late 90's Legacy. I scoured some junkyards and found a 2003 Outback LL Bean with seat heaters, one problem though, somebody had already hacked out the switches. I acquired some 1997 Legacy switches to use.
I pulled the seat heater elements out, and hacked out the wiring harness from door sill to door sill, not really knowing how much I was going to need of it. So I ended up with a bunch of cut wires at two ends and at the place for the switches, but I had the connectors for the seat heater elements.
Now I had to pull together all the required info required to combine 97 Legacy switches, with 2003 Outback elements and harness into a 2008 Forester XT Sports. It was hard to keep straight.
Here’s the Wiring Schematics I used
In the red I’ve circle the important things to note, Pin 4 on the B99 connector is common to Pin 37 on the relay block located under the left side of the dash. B99 is located under the carpet next to the passenger sill, it’s a large white connector.
I pulled apart the B99 connector and looked inside, Pin 4’s socket side (relay side) was populated and had the blue wire running to it. The pin side (seat heater side) was unpopulated. I quickly put a multimeter on Pin 4 in B99 and at the relay block and verified that the wiring exists, yes, it just dead ends there.
So now all I needed to do was continue the path over to the switches and elements. And then add some grounds.
Next I took the wiring harness from the 2003 Outback and mated it to the 1997 Legacy switches. For anyone with this very unique situation here is how they should be mated together
Pin callouts are referenced as this, remember this is the connector side; the switch side is a mirror image.
The wiring harness I had taken out at the salvage yard had way too much in it so I pared it down to what I needed.
Finally it was time to install the harness into the car. Seats out, center console out, gear selector trim out and necessary door frame trim pieces pulled so I can route under the carpet.
I took a pin and wire from another Subaru connector that I grabbed from the junkyard and used this to populate pin 4 of connector B99
This pin was slightly narrower than the other pins on the connector so I pulled the socket out of the other side and added a strand of copper to it to ensure good contact. It’s a good little trick.
Sure, it reinstalled into the connector a little crooked, but it will be close enough.
Wires then routed through their necessary holes and grounds grounded. I also spliced in the illumination wires to the light on my auto tranny gear selector.
I now attached my heater elements up and ran a test run. Everything heated up as expected. Phew, my wiring was correct.
Now I installed the heater elements in the seats. The other thread explained this pretty well, I’m not going to go into it.
Finally, time to re-install center console and seats, hook up connectors and reconnect your battery and your ready for the final test. Don’t forget to populate the top relay in the relay block, I used a relay I pulled from the same Outback that I got the elements out of.
Toasty seats confirmed.
The post I referenced above says you shouldn't bother with the illumination wires because they still light up, which is true, partially. If you don’t hook them up you still get power indication lights, but if you hook up the illumination wires you get the green seat heater symbol to glow when the lights are on instead of just the orange bars.
I like the illumination of these switches, but the bulbs were burned out so I had to replace the bulbs to get them to work. I used Radio Shack part number 272-1092
12V Microlamps (2-Pack) : Microlamps | RadioShack.com
These switches stick up higher than the standard ones the Forester uses so I am considering changing to those, but then I lose the nice green illuminated symbols, tough call.
From start to finish the install was about 8 hours. The seat elements install took a while, but now I would probably be half that time. I did spend probably 8 hours prior to that researching all the wiring diagram and testing switches as well.
Last bit of advice, don’t work on the seat on your carpet, the wife might get a little upset, they leave grease behind.
Total cost for this project was around $50. That will vary depending on salvage yards and where you source some items. Of course if you need to buy a soldering iron or other tools the price goes up.
