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4Runner Seat Heater

Nicole has wanted heated seat in the 4Runner for while, so I decided to get her the parts to do a seat heater retro fit. I had always planned on adding this when doing a leather seat conversion, but we ultimately decided against the leather conversion. I actually really like the cloth seats that come with the sport package. So one Saturday I left my day open and budgeted about six hours from start to finish. I started by pulling the entire seat out and bringing it into the house. Figured it would be easier and more comfortable to work inside and have the TV on in the background.

After looking the seat up and down and taking a few pics, just in case I needed some reference on how to put it back together, I started. First I had to take the plastic skirt off which also had the power seat and lumbar controls on it. Then came the business, I started to unsnap and unclip the fabric. Now all the fabric was disconnected from the seat frame and was only attached to the foam hog rings.

With every project I take on there is always a moment where I feel like I have gotten in over my head, this was it. I have always come out in the end thinking it wasn’t that bad, so I know when I this feeling of doubt I just need to keep going. And I did, by completely pulling the seat base cushion completely from the frame. Now I could work on unclipping the hog rings while comfortably seated on the couch. These things are a pain because of the accessibility. They tend to be tucked deep down in the seams of the cushion. After a few I got the hang of opening the rings. I have to say without needle nose vice grips this would have been nearly impossible. I was able to clamp the vice grip on one side of the ring, then grab my needle nose pliers and grab the other side and pull the ring apart.

With the fabric off the cushion, I was able to place the heating pad directly on the cushion. I notch out some of the cushion foam for the wire and some electrical parts and then put the fabric back on.

Getting the fabric back on required the help of Nicole, since I was reusing the hog rings and didn’t have ring pliers. I needed here to hold the fabric down and help expose the metal wire that I need to tie the fabric to with the rings. This took some time and patients, but everything went back on just as it did from the factory. I put the seat cushion back onto the frame and snapped the fabric back to the seat frame. I repeated the same steps for the back portion of the seat, except that I wasn’t able to remove the cushion for the seat frame.

Before putting the plastic molding back on to the seat I drilled a hole for the control switch.

Next I did the wiring while the seat was still out of the 4Runner. I thought this was going to go quickly because I am fairly proficient with DC circuits, but it didn’t. Since the heater unit didn’t have an automatic shut off, I didn’t want it to have the option to be on while the vehicle was off and drain the battery. So I need to find a 15A circuit that was only hot when the keys were in the ON or ACC position. Since this heater was pulling 15A, I didn’t want to piggy back on some other circuit or just tap into some ACC wire I found. I decided that I would wire through the firewall grommet into the engine compartment fuse box. An added plus was that there was already a 20A fuse for heated seats. This was going to be perfect. I tested it and it ended up being always hot. That wasn’t going to work. I ended up having to go to the fuse box under the dash and using an add-a-circuit fuse, which is only rated up to 10A. I searched for every alternative, but couldn’t come up with one. I decided to use the 10A add-a-circuit and use a 10A fuse and see if it would blow.

I put the seat back on and finished up the wiring from the fuse box to the seat and got all the trim put back. Next was to test it out. I turned it on low first. I could feel it getting warm and it didn’t blow the 10A fuse. I then switched it to high, still the fuse didn’t blow. I flipped it on and off a few times to see if I could get it to blow, but it never did. I am glad it is working with a 10A fuse. Means there is less power being pulled than what I thought there was going to be since the instructions said use a 15A.

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[ # 14561 ] Pingback from 4Runner Seat Heater Retrofit | Jason’s Eyes Blog [January 18, 2010, 12:05 pm]

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