1992 Lexus SC 400 Automatic Steering Adjustment

Tiny
MONT.AUTO
  • MEMBER
  • 1992 LEXUS SC 400
  • V8
  • 2WD
  • AUTOMATIC
  • 121,000 MILES
This vehicle facilitates the driver defining a particular steering wheel angle and location as a default when the car is being driven (the steering wheel stores closer to the dash and at the upper most angle when not being driven in order to simplify entrance and exit for the driver). If the automatic adjustment ceases to function but, the steering wheel's location can still be changed by manually manipulating the switch located on the steering wheel's column, what would you look for in order toto diagnose the problem?
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Monday, April 5th, 2010 AT 10:20 PM

9 Replies

Tiny
KEN
  • ADMIN
Hello, It sounds like the switch in the door jamb has either failed or the activation lever has broken. Please inspect so we can continue. Thanks for using 2Carpros. Com
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Wednesday, April 7th, 2010 AT 5:49 PM
Tiny
MONT.AUTO
  • MEMBER
Thanks for your note. We fiddled with the unit and got it to work but, I didn't completely understand your suggestions; for example, we didn't notice any switch in the door that was related to the steering wheel alignment and is the activation lever plastic? I mean, how could it break?

I tried to attach copies of Lexus SC 400 repair manual pages SR-3, SR-4 & SR-6 but, your computer software system wouldn't allow me to upload PDR or TIFF files. Do you have access to these manuals?

Have a good day.
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Wednesday, April 7th, 2010 AT 10:28 PM
Tiny
KEN
  • ADMIN
Hello, It looks like the switch in that model is intergraded into the door latch assembly. This switch is what sends the message to the controller to tell the steering wheel position to activate. If this switch fails the steering wheel will not move because it thinks the door is still open. You will need to test the switch inside the door to move forward.
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Thursday, April 8th, 2010 AT 1:17 PM
Tiny
MONT.AUTO
  • MEMBER
Thanks for your follow-up. Once the ingnition key is inserted into the ignition switch, the steering wheel repositions to the default position irrespective of the position of the door; that is, open or closed. Are you thinking about a later model?

The door switches mounted on the driver's side door on this model include a preset seat position switch (2 positions and a "Set" button), mirror alignment (both sides), dook lock (both doors), window lock and electric window switches (both sides). I couldn't find any switch in the door latch assembly. Please confirm.

Have a good day.
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Thursday, April 8th, 2010 AT 9:49 PM
Tiny
KEN
  • ADMIN
There has to be a switch that tells the comp was the door is closed, it is either in the door latch, or a pin switch in the jam. Please let me know which one you have.
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Friday, April 9th, 2010 AT 11:21 AM
Tiny
MONT.AUTO
  • MEMBER
Thanks for your interest. I haven't yet taken the door apart but, the Lexus manual states (pg. BE-76) that there is a "Door Courtesy Switch" internally mounted in each door and located below the exterior door handle (about half way between the handle and the bottom of the door). The manual implies the purpose of the switch is only to manage the interior courtesy lights when a door is opened; that is, no comment about any connection to the movement of the steering wheel.

Also, the steering wheel mechanism seems to be managed only by the switches on the steering wheel column and the ignition switch; meaning, once the ignition key is inserted, if the system switch is in the depressed position, the automatic steering wheel adjustment mechanism operates whether or not the door is open.

I could not find any pin switch in the door jam.

Does this help? Have a good day.
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Friday, April 9th, 2010 AT 7:36 PM
Tiny
KEN
  • ADMIN
Does the interior lights work when you open and close the doors, if so, there is an ECU that controls the steering wheel position. It is located under the dash on the left side. It has probably failed. I have attached an image. Please let me know how it goes.


http://www.2carpros.com/forum/automotive_pictures/10_lexus_steering_wheel_position_1.jpg

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Monday, April 12th, 2010 AT 12:54 PM
Tiny
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  • MEMBER
Yes, if the switch above the interior rear view mirror is set to the "Door" position, the interior ceiling light ignites when either door is opened. Does this help?

Have a good day.
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Monday, April 12th, 2010 AT 8:11 PM
Tiny
KEN
  • ADMIN
Ok, thats helps, it sounds like the problem could be the controller, try replacing it with a used one and re-check operation.
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Tuesday, April 13th, 2010 AT 12:04 PM

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