captclam

The guy who sold me my 1993 SC400 told me that the seat heater only work when it is cold outside. I figured this was a bunch of crap at the time... is it?

The fuse #16 seat heater fuse tests just fine. The lights come on on the switches but there is no warmth at all coming from either seat.

Very weird considering both are not working... which makes me wonder if the guy was right about the "thermal switch".

Any ideas?

emus1

I believe in that model year the temperature had to be below 70 degrees (might be wrong on the number) before seat heaters can be activated.

99 LS 400 Silver/Jade

captclam

Is this really true? Seat heaters only work when it's cold outside?

jahdish

there wsa a forum a few days ago in the gs forum about a guy wondering the same thing on i believe a 2k gs400 and lexus said that they won't work above 77 degrees so it is true about not working in warm weather it just the temp that is in question.

Mean Gene

Guyz - Don't know about the SC but the GS3/4 series shop manual ( page BE-185 ) states that the temperature range of the seat heating element is between 77 - 113 degrees Fahrenheit. I don't see anything that says would indicate that it won't work between those ranges - just cut off at 113 & above.

captclam

Mean,

Doesn't that mean that that is the range for the element itself? That it will shut off it it reaches higher that 113?

Any thermal couple between the switch and the heater element or any other switches in the wiring diagram?? Perhaps tied to another switch in series?? How many leads are on the heater switch, does it show? The light cannot come on and the heater not trip unless that switch is tied to something else...

Are there any 1992-95 SC300/400 folks reading this who can test theirs??

Kirko

Mean Gene

Kirko - That's the temperature range of the thermostat inside the seat cushions. Lexus says to use a light to check the thermostat connections for continuity. Below 77 degrees, U should have it & the seat warms. Above 113, no continuity so that would appear to be the limit of the heating. Like I said - this is from a GS manual but I'd think almost every Lexus with heated seats would use the same configuration - saves on manufacturing different vehicle specific parts. Good luck with the problem!

captclam

What I am saying is that the seat itself does not get warm when I have the switch turn on. I tried it with the heater on full blast also... very nice on a Sunny Indiana day of 98 degrees!!

Tried it this morning also, 72 and sunny- NOTHING.

I chased down the owner of a 98 SC400 and he told me his worked no matter what the temp and no matter what the heat/air was set at on the dash.

Very troubling. I will check under the seat with the flash light. Any other ideas? Were are the heaters? Are they actually inside the seats?

Very strange that both are dead, huh? Especially since the car spent it's whole life in West Palm Beach Florida.

Any idea would be appreciated...

Kirk