So...I just got a 95 sc400 yesterday and everything is great in the world. Until this morning. I hit the horn and the cruise control light came on. And when I turn the cruise control on the horn honks. Wtf? Any ideas? The air bag light has been on since I got it as well.
Thanks in advance

 

if you open the engine bay and look for the diagnostic port. theres two pins that you have to jump to turn off the air bag. I don't remember which ones but i'll try and find the forums about it. the previous owner probably just turned the key on with the guage cluster removed.
as far as the cruise control and horn, I would start looking for a wiring diagram and start following it. good luck.

 

http://lextech.org/forums/index.php?topic=9.0
heres one method.
https://www.clublexus.com/forums/sc-...bag-light.html
heres method number two.

 

check your wheel well harness. remove the driver side wheel well liner and check the wires.

 

you might have a pinched wire or other wiring issue behind the steering wheel. I would be careful since it involves the airbag all those items plug into a clockspring on the steering column.

 

I checked it a little while ago. And when I turn the wheel the cc doesn't affect the horn and as I turned it back and forth it did. I'm assuming somethings crossed in the steering column.

You sed the air bag light can be caused by turning the key on with the cluster out?

 

yeah it sounds like the clockspring has an issue if its when turning the wheel, havent heard of it on an SC before but wouldn't be the first car I have had the horn work at only a few positions.

airbag light is caused by having the key in when the cluster is out, or if the airbag is out and you put the key in.
to get the airbag light to turn off is an odd procedure generally called the "wire dance"

here is a guide, you dont have to make the switch shown, you can just tap the wires to ground instead while holding them, that is what I do too much time to make a switch.
https://www.clublexus.com/forums/sc-...bag-light.html

 

Can a diagnostic tool clear the airbag light without the "wire dance"? It doesn't really bother me being on. I got the car from a younger kid and I'm not sure what he did with it. I know it has the Nakamichi system. But I dunno what he took out or put in. What was supposed to come from the factory. Like, what is the normal and power switch for on the center console? Are there supposed to be relays in the Trac ports under the hood? I'm coming from a 81 celica. Lol kinda outside my expertise

 

i think you need to do some searching and reading on the forums, the SC has alot more electronics than an 81 celica that is for certain weren't those carbd 20r's or something.

you will have to do the wire dance, some people pull the cluster and remove the bulb instead (probably how the light went off in the first place was replacing bulbs in the cluster is most common), but the wire dance is actually pretty easy just need a couple wires and alternate touching them to a ground bolt. grab a beer and have at it wont take you more than 20 minutes, I can do it in like 2 minutes after doing it a few times.

nakamichi is just the upgraded sound system, doesn't do anything special to be concerned with just has a different amplifier and some speakers etc..

the normal/power switch is on most 90's toyota's it changes where the automatic transmission will shift.
so in normal it shifts early like a regular auto car (think camry), in power it holds the gears a little higher in rpm before shifting so it feels more sporty. dont think I ever took my old auto out of power mode, but overall its a small difference.

the trac relays will only be present (next to the 2 abs relays) if you have trac system on your car. it was an option on automatics so you either have it or don't. 5 speeds never came with trac.
My 5 speed has 2 empty spots for it, so if you are missing them you probably don;t have trac. if there is a trac light on your cluster though you might have had it at some point.
if you post a picture of the throttle body I can tell you if the engine is a trac engine or not.

 

Yeh I am constantly researching lately. Just with that issue I didn't even know where to even begin.


Me bringing up the Naka was just because I wanted to put my Bluetooth Hu in the lexus and realized how much surgery was going to be needed to put a single din hu. I've been reading up on that and it sounds like the infinity upgrade on the 240s that used the factory amp as well.

I can hold my own, usually, with working on cars, but in this case I'd rather ask than do the whole trial and error method. I really like the SC and want to avoid any issues. Other than what I have to fix already that is.


Thanks for your response!!

 

yeah no problem, thats why I gave you a few pointers, all in all it doesn't sound too bad its just some minor stuff.
They are good cars just as good as the celica if not better, but sometimes takes a little undoing of what the previous owner did. these cars often have cluster issues so seeing the airbag light on is very common, also if buying one with oddly low miles and paying premium, run the check on it to make sure its actual miles the clusters are way too easy to change out. most of these cars with higher mileage probably don't even have the original cluster anymore they get rebuilt so often.

mine is original though and I intend to keep it that way, take care of the car and itll last a long time, I have only ever had 1 bulb go out on me so far (keeping fingers crossed). I have had other Sc's though with literally no working bulbs or needles, not even 1.

the stereo thing its one of those with a seperate amp like the toyota bose or the nissan system, in the SC the amp is in the trunk under the CD changer.

the proper way to go to an aftermarket headunit in this car is to run new speaker wires for all 4 speakers (FR, FL, RR, RL) from the headunit down the passenger side of the car into the trunk where the stock amp is.
there is an in plug on the amp and an out plug, what you do is take the out plug, and wire your new 4 sets of speaker wires to the out plug which goes to the 4 speakers in the car. this is bypassing the amp and you get crystal clear sound.

the reason you can;t just do it at the headunit to the stock wiring, is that the stock amp only takes 2 signals and generates 4 signals, so if you feed the signals in to the stock amp, you get double amplification and not as good sound, also volume control becomes really odd.

sounds like a pain, but its only takes 5 minutes to remove the rear seats, and another 10-15 to run wire down the passenger side, basically it goes behind the glove box, behind the plastic mold thingy, runs under the plastic foot sill there (there will be a stock wire harness already there with clips just tie it to that), when it comes out the sill goes into another plastic thing next to the rear seats, up the side of the car and into the hole that goes into the trunk from the top of the rear seat. In the trunk you will see the wire hanging out there once you pull that grey lining, and then you make all you connections at the amp output plug, there is a wiring diagram in the general audio section which is used for all models for some reason.

after you do it a few times its really easy! I have done on at least 3 SC's that I can remember.
the CD cahnger and stock amp can also be removed, which makes a great spot for a relocated battery, or whatever you need more room for, like an amp.

I think there is a difference with the nakamichi system wiring and the sub a little bit, but can't remember that part, somehow I seem to get only SC's without the nak.