2009 sonata heated seat wiring

I'm going to be adding heated seats to my Sonata. I'm looking for a good place to tap into for the power feed. This thick black wire on the back of the fuse box is +12 all the time. Should I use this? I will use a relay so the heated seat only has power when the car is on. This car did have a factory option for heated seats, does anyone know where those would be hooked into? I'd love to just use the factory connection but I have no idea where it is. Thanks.

Zirconx-

  In the past, I have tapped into the heated seat switches directly.  You would need to remove the shift plate (Pulls up, clips only),

and then remove the 2 screws (1 on each side) at the lower portion of the side finishers were the switches are mounted.    Once the screws are removed, the finishers pull out (Clips only).   

On either switch, the switch output is the brown wire--it is activated by a ground pulse.   I have diode or'd the 2 switches together, i.e., I connected each brown wire to the non-banded side of a diode, then tied the banded sides of the diodes together and to the remote start (- pulse) output.  

The last one I did, a 2009 limited Sonata, I only had 1 output for AUX, so I also tied the defrost together (using a diode wired the same way), and needed a relay to provide the ground, as the RS output could not drive all 3.   It worked great;  1 press of th AUX had Defrost, both seats on High.  2 Presses, seats on low only; 3 presses defrost only; 4 presses seats on high only; 5 presses, Defrost on and seats on low, 6 presses all off.

Anyway, with only the seats hooked up, you would be able to toggle from High to Low to Off.

Lectric Guy

For the record, the Black  wire that you identify in your diagram as Hot always is the input to the the seat power fuse. The other side of the fuse is in the white 20 pin connector  Pin 1 (Thick RED wire)--the goes directly to the seat modules.  This is the connector above and left of the black wire.

There is another Pink wire (on the other side of the fuse box) that provides switched 12V, on with ACC and IGN to the heat warmer modules.

Lectric Guy

if you use a relay that is driven by an ign power source you could use this 12v as pin 87 off the relay to drive the heaters, but if you tap directly into this wire as power and you forget to turn the switches off youd drain your battery

Jim-

 You are absolutely correct.  I believe I misread the original post--It appears Zirconx will be adding aftermarket seat heaters.

 From the schematic of the 09 Sonata, it actually provides constant power to the seat warmer modules, as well as switched ignition power, as I listed above.   The factory modules are only active when the car is running--the modules require the car to be running to draw power.   That being said, for aftermarket seat heaters,  a relay (which shuts down when the car is off)  is the way to go, as you have stated.  

Relay wiring should be as follows:

Pin 86--12V source, on with ignition, through a fuse (The Pink wire used in th factory circuit is available in Red 20 pin connector , Pin 13 in the driver's kick panel--should be populated).

Pin 85--Control from the remote start output or seat switch

Pin 87--Black 12V constant through an added  fuse

Pin30--to seat  heater

Lectric Guy

no lectric guy, pin 86 to ign power, pin 85 to ground, pin 87 to constant power, pin 30 to seatheater power input wire, this way when ign is turned on relay ignites and sends the heavier voltage constant power out to the seatheaters and when ign is off seat heaters turn off

Thanks for the info guys, this is such a great site. I'm still a little unclear about what the heated seat output wires are. lectricguy I'm attaching a picture of what I think is the white 20 pin plug you are referring to. But I don't think I have a thick red wire on pin 1. Is that the empty spot at the bottom of the connector? My car might be missing this since the car didn't come with heated seats. Aha, yes now I see a little "1" in the pic (I'll circle it). So I guess I'm missing that wire on the plug. If I could come up with the right kind of pin I could attach a wire and then insert it into the connector, right? Then I'd be tapping into the factory heated seat fuse, that would be awesome. I have another question for you guys since you are very knowledgeable about the Sonata wiring. I just installed a remote starter, and I hooked my neg aux input to pin 18 on the BCM (connector B) so I could turn on my rear defroster. It works, but the odd thing is that the indicator light on the defroster button doesn't come on. When I press my aux button that light flashes for a sec but then goes out. But the defroster IS on, I can tell by watching the output on the defroster relay. I thought this might happen because I didn't power the 2nd accessory when remote starting, because I don't want the radio on. But here's the really odd thing, if I put the key in and turn it to the on position, the light still doesn't come on. But if I then turn the key all the way to off, the light comes on! Weird but at least the rear defrost is working.

I'm still a little unclear about what the heated seat output wires are. lectricguy I'm attaching a picture of what I think is the white 20 pin plug you are referring to. But I don't think I have a thick red wire on pin 1. Is that the empty spot at the bottom of the connector? My car might be missing this since the car didn't come with heated seats. Aha, yes now I see a little "1" in the pic (I'll circle it). So I guess I'm missing that wire on the plug. If I could come up with the right kind of pin I could attach a wire and then insert it into the connector, right? Then I'd be tapping into the factory heated seat fuse, that would be awesome.

As far as the factory seat warmer, it appears from your picture the constant power wire was omitted from the harness.   This is the pin 1 that you circled above.  The constant power  to the seat module is fused at 15A.  If that is consistant with your aftermarket seat heater power, then it is possible to add a wire in that location.  For that type of application, I would use a pinned wire--the wire size intended was AWG16. 

You could also just tap the black for your seat power,  just ensure that you use a relay powered by a source that turns off with IGN.  Fuse per the earlier post on this.

I have another question for you guys since you are very knowledgeable about the Sonata wiring. I just installed a remote starter, and I hooked my neg aux input to pin 18 on the BCM (connector B) so I could turn on my rear defroster. It works, but the odd thing is that the indicator light on the defroster button doesn't come on. When I press my aux button that light flashes for a sec but then goes out. But the defroster IS on, I can tell by watching the output on the defroster relay. I thought this might happen because I didn't power the 2nd accessory when remote starting, because I don't want the radio on. But here's the really odd thing, if I put the key in and turn it to the on position, the light still doesn't come on. But if I then turn the key all the way to off, the light comes on! Weird but at least the rear defrost is working.

Not sure on this.  It must be the ACC circuit.  Do the other dash lights come on?    The light on the defrost switch is powered by the defrost relay output...but its return goes through the dimmer.   The dimmer actually has 2 parallel circuits; one for the dash, and one for the interior indicators, such as the defrost.   If the dash is off, the defrost will be off also.  

Since you verified the defrost comes on, your options are:  live with this as is, or power the ACCY (Green) circuit.

Lectric Guy

lectricguy wrote: Not sure on this.  It must be the ACC circuit.  Do the other dash lights come on?    The light on the defrost switch is powered by the defrost relay output...but its return goes through the dimmer.   The dimmer actually has 2 parallel circuits; one for the dash, and one for the interior indicators, such as the defrost.   If the dash is off, the defrost will be off also.   Since you verified the defrost comes on, your options are:  live with this as is, or power the ACCY (Green) circuit.

Aha - you mentioned it goes through the dimmer circuit. I remember that I had the dash panel out (so the dimmer switch was disconnected) while I was testing. So I tried it again tonight now that I have my car back together - and it works! The problem was just the dimmer switch being disconnected. Also, what do you mean by "pinned wire" ?

Also, what do you mean by "pinned wire" ?

I mean a wire with a factory crimped mating pin.   Usually an old connector can be used for this--just depopulate one of the positions (usually this can be done with a small screwdriver).   It is possible to add a wire without a pin, but because this is a high current application I would not recommend that approach.  

Seems like alot of work just to use the factory fuse IMO.

Lectric Guy