The next weekend I tackled the wiring for the heated and cooled features. These seats don't use traditional seat heaters. They use a thermal electric device (TED) and a blower motor. The TEDs are capable of heating and cooling. They heat or cool the air that the blowers pass across them.
There is a TED and fan in the seat back and another set in the seat bottom. Wiring these up was a bit more complicated than I expected. I searched hard, but found no wiring diagrams online. I drew up a wiring diagram which should simplify things for you.
You'll need 2 double pole double throw DPDT switches, 4 relays, 2 red LEDs and 2 blue LEDs.
I was not able to find reliable information on wire color coding online, but I can talk you through this.
Finding the fan wires is easy. Each fan has three wires coming out of it, VIO, RED, & BLK. You're going to supply +12V to VIO and ground the BLK wire. You'll find it's easier to follow the VIO & BLK wires through the harness connector and connect up to whatever color wire Ford used rather than trying to get in the confined space next to the fan.
Next you'll need to find the wires to power the TEDs. Check the wiring harness coming out of each TED. Two wires are a larger gauge than the rest. Those are the ones you want.
You're going to experiment to figure out the polarity. Make sure your fan is on first. You would not want to power up a TED without air blowing across it. Then connect your TED wires, one to +12v and the other to ground.
Now check whether the TED is heating or cooling the seat. Note that if the TED is pushing hot air through the seat cushion then it's pushing cool air through its exhaust port beneath the seat. The reverse is also true.
If you reverse the wires to your TED, it will do the opposite function. If previously it was heating, reversing the wiring causes it to cool. Now write down the color coding of your wires So you keep the polarity correct.
Once you've identified the polarity of each TED, you'll tie the upper and lower TEDs together so that the polarity is consistent. that way the seat back and seat bottom are both cooling or heating together.
Now that you've figured out the polarity of your TEDs and have identified your fan wiring, you'll be able to wire up using the attached diagram
Note that using this wiring method eliminates any thermostat features that Ford had designed it with, to keep the seat from getting overly warm or cool. You'll simply switch off your seat when you're warm enough.
TROUBLESHOOTING
If when you switch your seat to cool it is actually heating, you've just wired your switches to the wrong relays. Pull the wires off of both pin-85 connectors and reconnect them to the opposite relay.
If when you switch your seat to cool you find that one cushion is cooling and the other cushion is heating, then you've just got the polarity of that TED backwards. Go back to the wires for the misbehaving TED and reconnect them opposite of what you had done.
NOTE
The color coding of the TED wires in my diagram is just for demonstration. You'll be using the color coding you wrote down when you figured out the polarity of your TEDs.
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