Heated seat conversion 2002-2003 (1 Viewer)

[ohlordherewego]

I am putting the seat cushions from a 2003 LX470 on to 2002 LX470 seat frames with electronics so I don't have to reupholster the 2002. I am having some issues with the driver's bottom seat heater, the 2002 has a 3 wire seat heater connector for the bottom but the 03 heater is a 4 wire connector. The top cushion is the same connector on both years. I am wondering what the extra wire is for? In the schematic two wires get jumped together, so that leaves me with the W-B and B-L wires. Here is the schematic, I am wondering if I can just connect the two wires that are left and treat them like one wire so its like the connector is a 3 wire one. Otherwise would I be able to just connect one?

 

[ClassyJalopy]

@Ayune ?

 

[kevgentile]

Both early and later seat heaters use a 4 wire set-up. The difference may be in the routing of the ground wire.
The '03 up run independently to the junction where as the pre-03 join prior to the junction block.
Post pics of the 2 connectors and the matching side in the wiring harness.

 

[Ayune]

@kevgentile is correct, the difference is in the ground connection (white-with-black-stripe). This color wire will always be ground anywhere in the truck, so feel free to connect it to the chassis wherever it may be left unconnected.

The seat heaters get their power from the red-with-lightblue-stripe and black-with-lightblue-stripe wires.

Below is a diagram from an earlier version (‘98) for reference. You can see how ground is connected directly from the heater elements instead of through the ECU as in the ‘03 diagram.