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Old September 18th, 2010, 11:43 AM   #1
hoo dat. wat.
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Default DIY Seat Heat - Teh Awesome!

The older I become, the nicer the "little things" in life become. One of those things is decent butt-warmers in my vehicles. Living in Michigan, there are many days that make it nice, plus I find it's nice to leave the van cabin cooler and stay warm with a good tushie-toaster.

What got me to thinking was when I was pricing out new pickup trucks (that didn't la$t long - new vehicle$ are co$t-prohibitive!) and I saw with some packages, seat heat ended up being a stealer, er, dealer-installed option. I hadn't even thought of putting heaters in existing seats!

So, looking at what kits I could find on the internet, I made my choice based on the cost/benefit ratio and found a kit that nobody could come close to touching (once I found it for sale at
Dorman 628-040 kit (About $65 as I write this) I ordered two sets and anxiously awaited their arrival. A quick note on, IMHO, they are my first stop if I can't find something locally. I order a lot of things from them and never have had a lick of trouble.

So, the kits arrive, and I open one up. The first thing you remove from the box is the wiring harness - and right off the bat, you know you have a quality kit. OEM-quality connectors, switches, and relays. The wiring is in its own loom and has heat-shrink on the ends to seal it nicely. I didn't undo the harness in the house, so I wasn't certain on the length, but once I did (during the install) - I can verify there is enough wiring to give your second-row passengers warm butts (for those of you with backseat drivers in the household?).
The seat pads are heavy cloth with two-sided tape already applied - two to a kit and they are both the same size.

Another thing I was curious about was the "Hog-Ring" pliers the picture of the kit shows - I verified the kit came with them before I ordered ( I hadn't looked under the seats to determine if I need them yet ). Well, I can't say they suck - because I didn't need them, but they are close to the size and feel of a tool one might expect from a $0.50 vending machine tucked in with the bubble gum and jawbreaker machines at the exit of your local grocery store. For the price, I am NOT complaining - just want to inform everybody. :)

Anyway, you can't really tell a good story on the internets w/o pictures, so I took some, but not enough for a step-by-step guide. Enough to get you DIY-ers the skinny and show you that it is pretty easy. :thumbup:

To start off, here is the instruction sheet (PDF).

I did this in an Astro van, it I listed GM - specific shiz. It all starts with an 18mm tool to remove your seats:

Remove the lumbar knob and recliner lever (IIRC, T25 or T27):

Remove the 4 - 12mm bolts and remove the seat track:

Now, all of the plastic clips that secure the bottom seat cover are accessible:

Seat cover peeled away, ready to be removed & kit packaging:

Kit out of the box and laid out on the 96 F250 workbench:

Picture of a mess. Please note the wiring harness - nice and long:

This is where I start to get a bit short on pictures. This is a picture of the bottom seat cushion and how it is attached to the seat foam to stay in place:

That hog-ring loops through the cushion and a flexible rod that looks like it is molded into the seat foam. I was able to employ superior envelope-stuffing skills to position the heating pad (and remove the tape backing) without removing the hog-rings. I feel confident stating I would royally goof up the way the seat cover fit if I even looked at those hog-rings sideways - so I'm very happy with the results. Even with my big hands, I could get the backing off of the tape and the pad positioned without any creases or folds.

For the seatback, remove the armrest and undo the two plastic "seams" at the bottom of the cover:

For the seatback, I expected more hog-rings, but was pleasantly surprised at this discovery (velcro!):

Prepping the heater pad before stuffing it in - you'll make the job much easier on yourself if you prepare the 2-sided tape this way prior to installation:

A shot of the installed pad before reassembly:

That's it! Throw the seat track and other external parts back on and go run your wiring harness!

I used the precut access holes in the carpet to run the wires:

Installed switch location right next to the aux input recently installed (small LED lights up red for Hi and amber for Lo settings):

I omitted where I ran the wiring, however, there was plenty of length available (including a 10A fuse & holder) to run to the interior power distribution box at the driver's feet. I pulled the box out (as far as the wiring would allow) then determined which circuit was on only when the ignition was on. I stripped a length of insulation away and spliced in the heater supply wires going to it. A better idea - which I didn't have the time for when I did this - would be to use the same circuit to trigger a sufficiently sized relay powered from B+.

Have at it!
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