Steering tilt & Telescoping not working

[Stanwithaplan]

Hi Gang, 

My steering motors don't work, its not the fuse and I've purchased two replacement motors they also show no signs of life.  I guess it could be a switch problem? Does anyone have a relevant wiring diagram please?

[messi]

I have a 99 ls400, the steering motor on mine is very temperamental in autumn winter, but come spring and summer when the weather is hot, it works without an issue. 

 

[steve2006]

Having done a bit of research I discovered that the tilt/telescope function can be turned off with Techstream so if it has never worked maybe worth a look.

As usual Lexus use a “Tilt and Telescopic Computer” to control the functions, I did have the full Lexus  electrical manual for this car but sold it on to a fellow member some time ago and cannot now remember who but if you are that member please chip in.

The only info I could find was part of the wiring diagram below.

I assume you have already checked any relevant fuses but the 2 associated fuses also power other things so unlikely.

[Stanwithaplan]

Many thanks Steve. Yep I've checked the fuses. I'll have a look at this tomorrow.

[Stanwithaplan]

I've also found a website with a comprehensive selection LS400 wiring diagrams for $14.99 (£12) if that helps anyone else?  https://portal-diagnostov.com/en/root/rukovodstva-po-remontu-on-line/elektroshemy/lexus/lexus-lexus-1999/lexus-lexus-1999-lexus-ls-400-1999/lexus-lexus-1999-lexus-ls-400-1999-lexus-ls-400-1999-all-wiring-diagrams/

[Stanwithaplan]

I wonder if it could be the power steering ECU? Does anyone know how to test this please or it a case of swapping out with another (they are available on ebay)? Sorry if this is a dumb question?

[BigBoomer]

It could easily be the Tilt & Telescopic Computer as much like all the other computers in the LSes built from 1998 onwards it was built using lead-free solder and that degrades with age. That is most of the reason why companies like SIA and others in the USA (and elsewhere) have built up a business from reflowing the solder joins on old Lexus/Toyota computer modules.

The system consists of the switch, the wiring, the computer and 2 motors, so if the switch is good and the motors are good, then try replacing the computer.
Also, don't forget it could be more than one fault. A short-circuited motor could have blown the power transistors in the computer or similar.

[Stanwithaplan]

I appreciate your help with this George, many thanks.

I've sourced an ECU on eBay, will have a go at swapping it out next week, when I've got my car back.

Cheers

Stan

[stericker]

Stan. Was there no reference to the wiring etc. in the DVD I left in the car for you ?

[Stanwithaplan]

5 hours ago, stericker said:

Stan. Was there no reference to the wiring etc. in the DVD I left in the car for you ?

Hi Anthony, yes I did use your cd, it gives me a breakdown of the parts but theres no real detail on operation and fault finding. I've enlisted help and weather permitting will start work again on Friday:0)