My passenger has been saying on the discomfort from the hardened leather, collapsed foam. With possible summer road trip on the horizon, I've tried to add foam on the bottom cushion and the help is very minimal. My question is that 1. anyone experience the same? 2. what's the best to fix the lower cushion and the leather cover. 3. The upper leather and cushion is integrated as a one piece "thing". How would aftermarket leather cover deal with the upper cushion if at all? Thx. v. much.

 

You can soften the leather with a quality leather feed. It will probably need to be applied multiple times.
This will also soften the feel of the seat.

If the foam has collapsed then your only option is new foam, or take the old foam to an upholsterer and pay a small fortune to have it replaced.
I don't think there is any option for aftermarket foam, but I believe there are a couple of aftermarket fake-leather covers available.

Alternatively, have your passenger sit in the limo back seat where they can have reclining massage seats that are probably nearly new (assuming your LS has those options).
On longer runs my better half prefers to sit back there which suits me as she doesn't restrict my sightlines there and I can mute her snoring by turning up the front speakers <LOL>

 

While our LS430 is not an UL, front / back seat sitting combination is sometime preferred mainly for space for longer haul. So glad to listen to your case as well. Let me try to soften the leather over the weekend and see what will happen.

 

I have an aftermarket foam pad over the drivers seat for a little extra comfort. Looks good and helps. I also replaced the seat foam with OEM foam a while ago and it helped some, its a DIY if you have the right tools and can follow instructions. The biggest challenge is getting the seat out of the car, it can be done by one person working alone but beware of sharp edges and wear heavy gloves. You will need hog ring pliers and a set of rings. . . .

 

Putting some more thoughts to the problem and consider more cost effective and factory resolution, I found the passenger seat discomfort doesn't appear on the driver seat. And the passenger seat discomfort is later identified as the lack of seat cushion length. Now this leads me to a potential solution by swapping a JDM driver seat base as a passenger seat. I am about to locate a local JDM wrecker. That JDM is not a cooler seat. My thought is to just swap the very base where the seat control panel and cushion length mechanism to my existing passenger seat. I can imagine both the seat control panel harness and the entire seat harness are different than the original passenger seat. Wire cutting and soldering work is expected. My questions are: 1. anyone had done this? 2. anyone has the electrical diagram on both the US spec. passenger and driver seats showing the harness wire colors and the motor it control? 3. if I gonna test the seat functionality indoor, will a wifi router 12v 1A power supply be enough to move the seat motor one by one empty load? 4. anyone thinks of specific challenge that may stop my concept before I purchase a wrecker seat for paper weight? Thx. v. much.

 

I have never understood why car manufacturers like to fit "lesser" seats on the passenger side. Are they not aware that our better halves often have a say in whether a car is purchased, or not?
It must have cost them more to fit a different seat for the passenger (one each for LHD and RHD) than it would cost to just make identical front seats for ALL LHD & RHD cars.
Of course on the LS the passenger seat is different because it has the driver side controls that the drivers seat does not have.

I'm pretty sure you won't be able to fit the moveable lower cushion from the JDM seat to the regular passenger seat, so you will have to replace the regular seat with the JDM one and figure out how to wire it up.
Most of the external wiring will be for connections to the seat memory controls (which you won't have on the passenger side), so you may be able to ignore those.

A 12v 1A power supply will struggle to power one motor at a time. You would be better off using a connection to a spare 12V battery with a 20A fuse inline.
Some seat motors can draw 20A when they hit a limit. Don't forget that the motor often has to work with a 420lb BigBoomer sat on the seat, so they are pretty powerful.

 

You made a great point. Before the LS430, we drove a 1997 W210. Both front seats are identical from number of memory to adjustment except no power steering column. And for any car, nothing you will directly touch more than the seat as a passenger. Both memory setting are often used. So, the LS430 is lacking the cushion length and memory. By comparison, that's a disappointment especially weighting in the super low W210 used price. The complication of a JDM seat swap also lead me struggle yet it may be easier than sourcing another car.


A Google photo illustrates the passenger and driver seat control panel.

 

I had a 2001 W220 before I got my LS430. The drivers seat was THE most comfy I have ever sat in. Beat the LS seat by miles.
The passenger seat had the same adjustments (including bolster) as the drivers seat and 3 memories as well, but my better half still found it uncomfortable.
She prefers the LS430 passenger seat.
We both hated the W220 (except for the drivers seat) as it was without doubt the most unreliable, even downright dangerous car I have ever owned.

Even with it's "inferior" but still pretty comfy drivers seat, the LS430 is soooooo much better than the W220.

 

Cheapness. I have a 2021 Lincoln Nautilus with the base seats (not the upgraded massage seats). Passenger side does not have a separate front / back raise and lower: just 1 motor for entire seat height: no tilt adjustment. To me, this is far worse than not having memory. The way the car rides and with several other cost cutting measures, I say the car is a luxury-like car at a luxury price. Having bought it used since it depreciates so fast, it serves it purpose, and is certainly a decent vehicle. No car is perfect. I'd love the LS430 to have a heated steering wheel, automatic high beams, and an electronic parking brake. But is is a 2005 car, so I get that those were less common, and my UL has adaptive cruise that I love. But I understand that it would be nice if the passenger seat were equally adjustable in any car. My Nautilus lacks adjustable cushion/thigh length even on driver side. I feel it as too short. It is my number one gripe, but the car serves its purpose (hauling stuff on long trips). I still go to my LS430 as preference for my daily get-around-town driver.

 

Great seeing everyone's experience. And this leads me to think what's the minimum I could do so that passenger seat is not hated. The JDM driver seat deal seems not going well anyways. I do not see the need of cushion length adjustment on the passenger seat but a permanent cushion length increase will fix 95% of the imperfection. Is there way to simply mount the seat cushion and inch forward? I think I am going to explore on this fabrication. The base frame is mostly steel. The magnesium die cast alloy back frame is untouchable.

 

Unfortunately, a ride beyond 5mins starts to trigger back pain turns to the passenger. How nice the remaining of the car becomes irrelevant and absent minded. That's exactly why I want to fix it if possible.

 

Another thoughts. Forget about JDM as they are too hard to come by. The evident of the stamped steel surprise holes kinda suggest the seat structure is symmetrical? Would the upper seat rail from the driver side simply swapped to the passenger lower seat rail? They are available on Ebay. I don't need the power cushion length adjustment. All I need is an inch lengthening of the passenger seat cushion which can be set and forget by cranking the adjustment rack and pinion.