I have seen a number of threads on swapping 04+ Grand Prix heated seats into 97-03 models, such as this one: http://www.grandprixforums.net/seat-...-03-a-279.html
In most of these threads, I see a lot of people asking how to wire up the passenger side seat, with virtually no answers. I did see a thread where someone mentioned splicing into the heated seat switch wiring and running it to the passenger seat, but this provided no detail on how they ran the power or ground wires. I followed their suggestion for wiring up the passenger side seat switch and will provide the instructions in this write-up. There may be a variance in the wiring throughout the years, so these instructions may not work for your application. I also recommend disconnecting the battery when running any new wiring just as a safety precaution.
My car is a 98 GTP, and my seats are from a 2006 Grand Prix GT. They cost me $40 from the junkyard. I don't like cutting factory wires, so I made an adapter on the drivers side seat by cutting off the old plug from my half junk seat, and wiring it to the plug for the 06 seat. I followed the instructions for the wiring from the thread I linked above, and are as follows if you are too lazy to look yourself:
Driver Side Wiring:
99 GP (Connector c311)
--------------------------------
Pin A-Fused Battery Feed - Orange (larger gauge wire)
Pin B-Ground - Black
Pin C-Fused Battery Feed - Orange (smaller gauge wire)
Pin D-Seat Belt Switch Input - Black/white stripe
Pin E-Heated Seat ON Feed - Blue
Pin F-Heated Seat Low/High Input - Pink
05 GP (Connector c311)
--------------------------------
Pin A-Battery Positive Voltage - Orange
Pin B-Driver Heated Seat Cushion Temperature Sensor Low Reference - Yellow
Pin C-Battery Positive Voltage - Orange
Pin D-Driver Heated Seat Relay Control - Purple
Pin E-Heated Seat Cushion Temperature Sensor Signal - Yellow/black stripe
Pin F-Not Used
Pin G-Ground - Black
Pin H-Seat Belt Switch-Left - Black/white stripe
Pin J-M-Not Used.
Connections:
Pin A to Pin A (+)
-Orange to Orange (larger gauge wire)
Pin C to Pin C (+)
-Orange to Orange (smaller gauge wire)
Pin B to Pin G (-)
-Black to Black
Pin D to Pin H (Seat belt)
-Black/white stripe to Black/white stripe
Pin E to Pin D (heated seat on feed/Driver Heated Seat Relay Control)
-Blue to Purple
Pin F to Pin B and Pin E (Heated Seat Low/High Input/Driver Heated Seat Cushion Temperature Sensor Low Reference and Heated Seat Cushion Temperature Sensor Signal)
-Pink to Yellow and Yellow/black stripe
I followed the same logic when wiring the passenger side seat, in that the seat will only work on high.
What you will need:
- c313 connector that has wiring for the BCM and heated seat relay on the 04+ passenger seat.
- an extra heated seat switch, wiring pigtail and heated seat switch bezel. I would recommend getting two of each if you can score them cheap from the junkyard.
- an unpinned wire from a fuse box to provide power to the heated seat relay
- wiring to run from the heated seat switch to the seat, and a ground wire.
- Soldering tools and heat shrink tubing
Note: When I mention "guide pin", I am not actually talking about a pin, but rather a straight piece of plastic molded on the side of the connector that ensures you cannot plug the connector into the wrong plug.
First off, you will want to make a bezel two accommodate two heated seat switches. There are threads on this, and I will post a few pictures of the one I made. You need two bezels, cut them in half, and glue them together. The bezel measures about 4", so I cut both bezels at the 2" mark with a small cutoff wheel. You will also have to remove a small guide pin off the passenger side half that will prevent the finished product from fitting in the center console. I sanded the underside of each piece where they would meet with 80 grit, and used a thin strip of aluminum and JB Weld (24 hour stuff) to bond it together on the bottom. I then placed it in the center console to let it dry. It was wanting to pucker up in the middle where the two halves met, which is to be expected since there is some spring tension that holds the bezel in place. I placed a weight on the bezel to keep it flat, and let it dry overnight. I then cut a V groove down the middle on the top, and filled with JB weld, and again let dry overnight. I topcoated this with body filler, and painted. I don't have any pictures of the finished product, but once you are finished, you will have to modify the extra heated seat switch so it will fit the bezel correctly. There is a guide pin on the side of the switch that you will need to remove, or else it will not fit the bezel and could possibly break the mounting tabs that hold the switch in place (I know from experience).
Moving on with the wiring. I made an adapter that plugs into the stock plug for the drivers side heated seat switch. I am unsure what the name of this plug is, but noticed that this plug is used on a Chevy Blazer power mirror adjustment switch. I also noticed in the overhead center console of the Blazer, it had this same connector dangling where the dome light normally would be. I'm guessing it is common used in some GM interiors. The connector I am talking about looks like this:
It is identical to the plug on the heated seat switch, except the "guide pin" molded on the male plug is in the wrong spot. You will have to remove this on the heated seat switch plug on your car to plug it into this adapter plug. You can see what I am talking about in this picture:
The bottom connector has the guide pin removed, while the top one is still in tact.
You may have to unpin wires on the female adapter plug so they correspond with the heated seat switch wiring. Just ensure that the wiring is the correct size when doing this. When you wire up the passenger seat switch, you will share three wires with the drivers side switch. This is the grey wire, which is for dimming the lights on the switch, the brown wire, which provides power for the lighting of the switch, and the black wire, which provides a ground. Connect the blue and pink wires on the drivers side switch to the adapter, and leave the blue and pink wire on the passenger side switch free. You should have something like this:
Of course, you can skip all this by splicing the passenger switch into the wiring on the car, but I like being able to undo my modifications.
Now we need to remove some useless wiring from the c313 connector on the passenger seat. The wiring is as follows:
Passenger Side Wiring
06 GP (Connector c313)
Pin A-Ground - Black - Hook up to ground.
Pin B-Not used
Pin C-Passenger Heated Seat Cushion Temp Sensor Signal - Grey - To Pink wire on 98 GTP switch
Pin D-Passenger Heated Seat Relay Control - Tan/White - To blue wire on 98 GTP switch
Pin E-Not used - Mystery red wire.
Pin F-Passenger Heated Seat Cushions Temp Sensor Low Reference - Pink - To Pink wire on 98 GTP switch
Pin G-J - Not used
Pin K-Battery positive voltage - Orange - Run to fuse box
Pin L-Not used - BCM Ground - Black/white
Pin M-Not Used - Occupant sensor serial data link - Pink
Pin N-Not Used - Passenger Air bag on indicator - Dark Blue
Pin P-Not Used - Passenger Air bag off indicator - Dark Green
Pin R-Not Used - BCM battery voltage - Orange
Pin S-Not Used - BCM ignition voltage - Yellow
Remove the wiring I have labeled as "Not Used", and you should end with the connector looking like this:
Once that is done, you will want to remove the seat and prop it up out of the way so you can run the wiring.
Easy enough.
I ran the blue and pink wires next to the AC duct work under the passenger seat to the center console. Make sure these wires don't get pinched when the seat is installed. I took a picture, but my flash refused to work since the phone was almost dead. In this picture, the wires aren't tucked under the center console:
These wires get soldered to the pink and blue wires on your passenger switch. The blue wire gets soldered to Pin D-Passenger Heated Seat Relay Control (Tan/White) on the c313 connector. The pink wire gets soldered to two wires, Pin C-Passenger Heated Seat Cushion Temp Sensor Signal (Grey) and Pin F-Passenger Heated Seat Cushions Temp Sensor Low Reference (Pink).
Now for the power and ground wires that run to the heated seat relay. I turned to the fuse box on the passenger side, next to the glovebox:
Your car may be different from mine, but if you look closely, you can see a lone wire with no fuse in place. This is the second row from the bottom, second position from the left. This is originally labeled as something HVAC related (Forget the exact wording), and is 20 amps. It only has power when the ignition is turned on. All you have to do is remove this guy from the side of the fusebox:
And find a wire with the correct end to fit into place, so that you will have a fused power wire. Again, make sure it is at least as large as the corresponding wire on the c313 connector. You should be able to rob a wire off a junkyard car, and simply unpin it from the fusebox. The connector looks like this:
It is a bit of a pain getting the fusebox loose and twisting it around so you can insert the new wire, but it isn't impossible. I found it easiest when orientating the fusebox as such:
Once you have the new wire installed, insert the retaining clip you removed so no wires get ripped out of the fusebox in the future. Don't insert a fuse just yet. Wait until the wiring is finished before doing so, unless you have the battery disconnected.
Now for the ground. I used a factory ground behind this fusebox for my car, but later found one that is easier to get to and is closer to the seat when I ran my wiring.
The ground I used:
The ground I found after removing the kick panel on the passenger side under the carpet (Ignore the cobwebs and power wire for my amp):
I ran both wires through some wire loom near the fuse box, as the metal bracing for the dash has some sharp edges. You don't want the power wire rubbing on that!
I then removed the kick panel and ran both wires under the carpet, near the factory wiring that is already there. Both wires exit with the blue and pink wires near the AC vent under the passenger seat.
I then soldered the power wire to Pin K-Battery positive voltage (Orange ) and Pin A-Ground (Black) on the c313 connector and then taped the wiring up.
Here it is on my soda stained carpet:
I then reinstalled the seat, installed a fuse, plugged it in, and everything works as planned so far.
I hope this can help somebody out, and if you have any suggestions, let me know!
Also, I am not responsible for you catching your car or ass on fire.
