Installing Aftermarket Heated Seats

[OMW2SKI]

I ordered Dorman 628-040 seat heaters for my 2018 Big Horn. This kit comes, more or less, prewired including a relay and fuse tap with inline fuse.

I'm looking for an easy power source. I don't foresee adding other electronics down the road, so I don't necessarily wanna add a fuse box and relay setup behind the radio. I also want to be careful what I tap into because the heated seats probably create a bit of a draw. I want a safe install - and something that doesn't mess with the other electronics and control module (which I hear is notoriously sensitive).

I was thinking about tapping into the power outlet on the dash. I think that circuit is rated for about 450 watts. Any thoughts? This is easy to access and the existing wires in the kit are long enough to reach.

 

[chrisbh17]

IMHO the right way is to run positive right back to the battery, pick up a ground and a trigger from the interior of the truck and wire up a 12V relay.

Dont need a fuse box or anything (the +12V from the battery should be inline fused, though), and since you need to run wiring anyway its not much more trouble to go to the battery. Can modify the clutch delete plate to run the wire through so its easy to get through the firewall.

I ran aftermarket seat heaters in the rear of my truck, using the above installation. Under the front driver seat I tapped into ground and one of the pink/yellow leads (which are switched power) as a trigger for my relay. Grounded the seat heater wiring itself to a nearby bolt in the rear seat.

 

[OMW2SKI]

IMHO the right way is to run positive right back to the battery, pick up a ground and a trigger from the interior of the truck and wire up a 12V relay.

Dont need a fuse box or anything (the +12V from the battery should be inline fused, though), and since you need to run wiring anyway its not much more trouble to go to the battery. Can modify the clutch delete plate to run the wire through so its easy to get through the firewall.

I ran aftermarket seat heaters in the rear of my truck, using the above installation. Under the front driver seat I tapped into ground and one of the pink/yellow leads (which are switched power) as a trigger for my relay. Grounded the seat heater wiring itself to a nearby bolt in the rear seat.

Thanks for the feedback. I've seen write ups with similar installs. I guess I agree that it's probably best, but not 100% necessary. Watched a lot of Youtube videos where "professional amateurs" lol find other safe power sources.

The way this kit is wired, it would be much cleaner and easier to find something in the cab. I was kind of hoping to find someone who could confirm whether or not my idea to tap into the power plug is safe and reliable.

 

[chrisbh17]

It does look OK....the inverter is on a 30A circuit. If its the same as my 2017, the power to the inverter is under the passenger seat (where the inverter module is) and is a red/green wire.

It is connected to the Run/Accessory relay, so technically you could run the seat heaters in accessory mode (for better or worse), just something to note in case you anticipate them being left on without the truck running.

Per the instructions on your seat heaters, it looks like each side requires 10A, so the 30A circuit is more than enough.

 

[OMW2SKI]

It does look OK....the inverter is on a 30A circuit. If its the same as my 2017, the power to the inverter is under the passenger seat (where the inverter module is) and is a red/green wire.

It is connected to the Run/Accessory relay, so technically you could run the seat heaters in accessory mode (for better or worse), just something to note in case you anticipate them being left on without the truck running.

Per the instructions on your seat heaters, it looks like each side requires 10A, so the 30A circuit is more than enough.

Thank you! That's great info.

 

[OMW2SKI]

It does look OK....the inverter is on a 30A circuit. If its the same as my 2017, the power to the inverter is under the passenger seat (where the inverter module is) and is a red/green wire.

It is connected to the Run/Accessory relay, so technically you could run the seat heaters in accessory mode (for better or worse), just something to note in case you anticipate them being left on without the truck running.

Per the instructions on your seat heaters, it looks like each side requires 10A, so the 30A circuit is more than enough.

Finally got around to installing the heated seats. It was much more of a project than I anticipated lol... The Dorman heated seats are great though. They get warm fast!

I grabbed power from the plug going into the inverter. However, it supplies power even when the truck is off and the keys are removed. Somehow I forgot to test this before getting everything reassembled.

I guess I'm gonna grab a fuse tap and run a wire from the fuse box.

Anybody know off hand what fuse number I could tap into that would only provide power when the keys are in and in accessory on position? I think the fuse the radio is on would work fine, right?

 

[KC Cryptkeeper]

Do you have a jump seat? I thought if so, the 12v outlet in it is switched with the key, you can use it to switch a relay and still have the inverter wire as power dedicated to the seats. It would be less work if you understand relays.

 

[chrisbh17]

In one of the connectors under the front seat (cant remember if its the gray or the yellow one), there will be 2 pink/yellow wires coming from the chassis side. Each of those is a switched 12V.

AFAIK they are both switched on when the key is in "Run" (you can verify with a multimeter). I know you mentioned accessory position, but I avoided that because I didnt want the heaters to draw down the battery if I happen to be listening to the radio and the kids left the switch(es) on.

Also, IIRC, Run relay is disabled during cranking, so if the heaters are on while you start the truck they wont draw power away from cranking.

I used one of those pink/yellow as a trigger for a standard 12V automotive relay. Lots of good resources on the net about how to wire up a 5 terminal 12V relay....basically one is a trigger, one is a ground, one is incoming power and one is outgoing power (there are technically 2 outputs, one connects only when there is no trigger signal, one connects only when there IS trigger signal). The trigger basically causes a connection between incoming power to outgoing power.