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plmskier

Heated Seats

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Hey Guys...

My name is Paul, and trying to help trbl shoot my dads lexus 1996 LS 400-430? He replaced the heated seat indicator moduals, but that is not the issue as the old/new both lit up. So you can put the seats on "heated seat mode" everything lights up but seats are cold. I tried to do a search but not seeing to much info on this subject. Can anyone point me in the right direction to prior forums or steps to resolve or replace.

Thanks for the help.

Paul

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very common on older cars that the heating elements go bad.. They are flexible and it's not uncommon for them after a certain amount of flexing, ie, sitting down the heating elements break and they stop working..

I would start there.. Unfortunately replacement involves taking the skin off the seats, unless both seats don't work then suspect something else, but more than likely it's the heating elements in the seats themselves.

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very common on older cars that the heating elements go bad.. They are flexible and it's not uncommon for them after a certain amount of flexing, ie, sitting down the heating elements break and they stop working..

I would start there.. Unfortunately replacement involves taking the skin off the seats, unless both seats don't work then suspect something else, but more than likely it's the heating elements in the seats themselves.

Yes, both driver/pass seats are not working. Both heated light seat indicators come on though. Bad connection/fuse.... Is replace ment hard/expensive or better buying new/used seats?

Paul

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OK

In that case, probable not the elements, that would be extremely rare for both.. Yeah, something else going on like the module, or a fuse or something..

Need someone to post an electrical diagram of that system so you can start measuring voltage. Sorry, no help I don't have diagrams.

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It seems like I'm posting the same information lots of times lately -- must be because of the very cold weather!

There is a diagnosis procedure for heated seats in the repair manuals for your car and on online Lexus Techinfo. The procedure mostly involves checking resistance and continuity on the various connectors of the seat heater system. It can get expensive just replacing components without understanding what the real problem is.

The seat heater diagnosis procedure for my 00 LS takes up 11 pages -- too much to try scan and post and it probably isn't the same for all models anyway.

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OK

In that case, probable not the elements, that would be extremely rare for both.. Yeah, something else going on like the module, or a fuse or something..

Need someone to post an electrical diagram of that system so you can start measuring voltage. Sorry, no help I don't have diagrams.

Thats ok. So would it be possible to have a fuse blone for the seats not to heat but a sep fuse for the heated seat indicator lights? I've also read forums about not enough voltage comming to the seats or a thermostat in the seat? IDK I plan on researching this issue today and go home look at my dads car. Its been -20 for like 2/3 days in a row in VT so my dad wants his seats fixed lol.

Thanks for help. Maybe I will try a voltage meter on the connection under the seat when calling for heated seats...see what kinda power gets pushed to the seat.

Paul

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OK

In that case, probable not the elements, that would be extremely rare for both.. Yeah, something else going on like the module, or a fuse or something..

Need someone to post an electrical diagram of that system so you can start measuring voltage. Sorry, no help I don't have diagrams.

Thats ok. So would it be possible to have a fuse blone for the seats not to heat but a sep fuse for the heated seat indicator lights? I've also read forums about not enough voltage comming to the seats or a thermostat in the seat? IDK I plan on researching this issue today and go home look at my dads car. Its been -20 for like 2/3 days in a row in VT so my dad wants his seats fixed lol.

Thanks for help. Maybe I will try a voltage meter on the connection under the seat when calling for heated seats...see what kinda power gets pushed to the seat.

Paul

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My 1995 LS400 is doing the exact same thing. I got a schematic from the library which showed that if the light comes on all the fuses involved are ok. On my 95 there is a red/yellow wire which supplies the voltage to the drivers seat heater. This wire is larger then the others arround it since it carries more current. I lifted my wood center console to get at the switches. There are a couple of good posts on how to do this with out hurting the wood. On mine I confirmed voltage when the switch is made, both at the switch and also at the connector under the seat. This would prove everything to the heater element is working. The last thing I did was measure the resistence at the red /yellow wire to ground. A heater element should have a measurable resistence if it is not burned out. In mine the resistence was infinite so the elements are burned out. The only last possibility which I did not have a way to check out was that the heaters typically have a built in thermostat to open the circuit if it gets too hot. I think this would be built into the seat heater element. So I am at the point of needing to peel the seat leather off to fix this or replace the heater elements and I am not quite ready for this job. Let me know if you find anything else, but in my case I am pretty sure that the elements are shot and that I would need to remove the leather to fix this. I also started looking for a heated seat cover to use in the winter. The ones I have seen so far are not very warm or comfortable, but this might solve my problem with out messing with the seat covers. Good luck.

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All toyota's from the 90's have vauge seat heaters.

If your charging system is not perfect with 14vdc it will not function.

Start by replacing the batery and alternator wires.

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