verysage1

Help Help.

Lexus is stumped. Hello forum! My stalks, head light/turn signal and wiper/wash (called a master switch) intermittently stop working. Replaced the master switch and clock spring, TWICE! Works for a few months, then stops, works, stops….! dangerous at night.

Lexus wants to start replacing ECMs, until it stops!!! Ugh

Does anyone know why this happens? If an ECM, which one? If a loose ground wire (my guess), where?

2005 SC430 original owner.

(This site hangs up when I try to upload a stalk picture.)

Helpless in Philly…

oneround

I drive a 2002 so not sure how much this helps for a 2005, but...

For 2002: There is a 14-pin connector (C11) at the base of the steering wheel on the output side of the spiral cable. The signals from both headlamps and wiper pass through that connector. The ground wire is on pin 8 and is white with a black stripe.

For C11 - some things you could check with a volt-ohm meter (VOM).
pin 1−GROUND : Always approx. 12 volts
pin 2−GROUND : Approx. 12 volts with ignition SW at ON or ST position
pin 8−GROUND : Always continuity




The same ground also seems to have some relation to the tilt/telescope action of the steering wheel. Have you noticed if that works when the lights & wipers stop functioning?

verysage1

Thank you. Haven’t tied telescoping controls. I will next time they’d stop working. Great info 👍

DshngDaryl

When u say TWICE, do you mean you replaced both twice or the clock spring twice?

I think the best bet is to wait until it happens again and then diagnose it using a multimeter like @oneround said. Or if you are not comfortable with that, you can just replace the clockspring and see if that is the problem.

They say if you make a lot of U turns or fully rotate your steering wheel a lot, the clock spring goes out. in fact if you google "Clublexus.com clock spring" you will find it is a very common problem with some people having to replace it two or three times over the life of their car.

Also, do you have any aftermarket items, like an aftermarket stereo that is tied into your steering wheel controls?

AND, just to clarify, when you say your Steering wheel controls, do you mean your radio buttons, or your turn signals?

verysage1

Telescoping also stops working. Good task. Thanks

oneround

OK, then you likely have either a corrosion problem (on ground wire or power wire - at fuse box?), or a wire has some insulation missing and random car motions make it short out.

Get a chance to check ground and power at the C11 connector (let me know if you don't know where it's located or you need a diagram). All the systems you mentioned branch out from C11.

Any chance of a rodent problem with the wiring?

verysage1

thanks. We have multiple cars. Haven’t had a rodent issue so far, so I am assuming no.

Per the above post, maybe I’ll use a continuity tester on Pin 8 of C11. Grounded to the frame? Or fuse box ground? What do you think?

Since my original post, I lost Master Switch (MS) functionality 3 times - all when the car was cold. When the interior warms up, presto, MS works.

I am checking for fuse corrosion tomorrow.

thank you

oneround

You can pick any two places you think make a good ground and check continuity between them. Assuming that works then use either one of them to check for continuity.

I don't always write in a clear fashion. To clarify, test for continuity using pin 8 on the side of the connector with wires going off under the dash in a bundle, not the part that is affixed to the steering column base andthat comes out of the spiral cable device.

If the ground is good then you will have to test the power connections.
If the ground is bad you would have to trace wire continuity back to the ground termination point. The ground wire for my 2002 is white with a black stripe and goes from C11 at the steering wheel to junction box 4D, which is located above the glove compartment.

verysage1

Thanks DD...trying this in the AM

verysage1

Thanks Lee