YODAONE

1999 LS400 not optioned with heated seats.

I recently acquired like new drivers side seat cushion and seatback covers with pads. (Cypress)

The replacements driver's side does not have seat heaters.
However a cypress passenger side seat assembly in excellent condition from pick and pull yard does..and have installed it.

Model.year 1995 - 1997 LS400 heating elements under foam pads, while 1998 - 2000 are affixed under leather seat covers. (See attached Lexus TSB)

While original drivers seat is extracted and disassembled, have installed a black seat in excellent condition from a 1999, which has heating elements.

Reviewed several posts on topic for installing seat heaters and it appears it is not a one hour plug-and-play proposition due to different wiring harnesses

The seat assembly with heated seats uses different wiring harness to accommodate the heating element pad(s), yet it all runs through main seat connector...

I acquired a center console with seat heater buttons and am wondering if the stock dash harness to amplifier incorporates harness plugs (tucked away?) for heater switches, or in the case of Pioneer radio different harnesses with optional seat heaters.

Should wiring harness be suitable is fusebox wiring standardized?
Different fuse(s) and relay are in place...or different

I have a complete Nakimichi system; Control head, CD player, all door speakers, sub woofer AND correct dash - amplifier wiring harness...which I am planning to install...
Apparently the Nakimichi radio option came only with heated seats...

I mention because the Nakimichi harness does incorporate harness connectors for seat heater switches.

Soo, adding heated seats AND Nakimichi at same time makes more sense..


Center console plate depicting Nakimichi optioned wiring harness plugged into seat heater switches (top).


Entire dash wiring harness for Nakimichi option depicted

Located this post:

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/719940-96-ls400-adding-heated-seats.html

Kansas writes:

Yes, it is a difficult task. There is absolutely no infrastructure for heated seats in LS400's that did not have them installed at the factory. There is no wiring or connectors for them either at the seat or where the switches for them would be installed. There is no existing connection to the fuse box.
On LS400's with heated seats, the wiring for them is part of the larger interior electrical harness - not separate. It is not like you can just strip a separate heated seat harness out of an LS400 with heated seats and install it and the connectors in a car that does not have heated seats. Even if you were going to fabricate the harness, you would still need all the necessary connectors from the car with heated seats ... and the console wood panel that has the switches. And you would have to have the electrical diagrams and knowledge to wire them up.
On top of all that, heated seats from a 1996, 18 model year old car may have broken heating elements or elements that may not last for very long."

Sure it can be done - anything can be done with knowledge, time and money - but it is far from an easy task."

Kansas refers to 1996 LS400....

Possibly the 1999-2000 wiring harness is more standardized at fuse box than earlier models?

Also wondering if the body wiring harness to drivers seat connector on 1999 -2000 is standardized whether heated or unheated seats.

Thanks

YODAONE

Acquired front driver and passenger seats with working heating elements and I center shift plate wood surround panel with seat heater switches from 1999 LS400.

15A fuse in fusebox slot labeled front seat heater is pre wired.


Universal wiring in place from factory, so there exists a harness connector that plugs into the heater switch.


Center console wood panel removed. The seat heater switch wiring harness plug is secured via a blank connector shell affixed to support behind ashtray.

A closer view of heated seat switch harness plug removed from connector shell blank.

Engine compartment fusebox diagram depicts front seat heater fuse slot 7 up on left row.


Seat switches are alternate actuation. Here depressed and illuminated.

Close-up image of functioning seat heater switches.

Pioneer radio system harness shown

Seats warm quickly.

DGMD

Awesome. Found my next project. Thanks yoda.