SC430 Cruise control not working

[Flatfish42]

Hello, I wonder if anyone can help me? I  bought a Sc430 2004 model back in April with full 15 yrs of Lexus service history and apparently no problems. The car went back for a steering wheel airbag recall in November, and I took the opportunity to get the car serviced at the same time by our local. Lexus dealership. No problems noted. The car is not in everyday use, so it was not until a couple of weeks after I got the car back that I noticed the cruise control light comes on but I can’t set the speed. As the car was due for an MOT in January, I booked it in a month early at the Lexus dealership and asked whether they could check if anything had been disconnected / damaged during the airbag replacement process that would have lead to the CCnrl fault. The initial answer provided by the dealership was no fault was found but when I said this was clearly not the case they rechecked and said it was a switch problem that would cost between £400-£500 to fix. When I said there had been no fault prior to the airbag replacement, the response I received was that the switch doesn’t get touched during the airbag replacement process and therefore it was a pure coincidence that the switch now doesn’t work. Nothing they had done nor Their workmanship was at fault.

To be quite frank I am a bit suspicious of this explanation and I would appreciate any suggestions/ guidance on whether this is a feasible diagnosis or I should further challenge..Also, are there any other solutions worth trying to fix and if the switch is faulty, any recommendations on realistic price to fix or whether worth going to independent?
 

Any responses much appreciated.

[Neil E]

It could be coincidence but the cruise stalk is on the steering wheel. If the cruise light on the dash is illuminated then that would suggest the cruise stalk is connected correctly. 

So in 'Drive' above 30 mph if the stalk when pushed up and down to set the speed doesn't work that suggests the contacts in the stalk could be the issue. If you're okay disconnecting the Battery and removing the steering wheel with a suitable puller then it's a fairly quick task to swap the stalk for a good secondhand part. 

[Flatfish42]

Many thanks for your quick response. Whilst I’m not adverse to diy stuff, I’m a bit wary of playing about with steering wheel due to possibility of setting airbag off which I assume would need to be disconnected/ removed.  Don’t know whether I’m being too cautious or not there. I see there are a number of pullers for sale on amazon , eBay etc and a few videos on YouTube on steering wheel removal so will investigate further. Thanks for tip and Happy New Year!

[Britprius]

This could be a problem with the "clock spring spiral" in the top of the steering wheel. It consists of a plastic ribbon coiled up with thin wires embedded in it in the form of a clock spring. It's job is to allow the rotation of the steering wheel while maintaining the required electrical connections from the steering wheel control buttons, and switches. In time the embedded wires can crack due to metal fatigue as the spring is wound in either direction.
It is unlikely that this was cause by an airbag change as the airbags  removal only requires a couple of holding screws removing, and a cable connector disconnected on the back of the airbag. Nothing is touched in the wheel itself. 
If the clock spring is at fault it is highly likely that other steering wheel controls will start to fail as the weak spot in the coil progresses.

The clock spring is sold as a complete unit in a housing with plug type connectors at the inner, and outer ends. It comes locked in it's central position, and has to be fitted with the steering in the strait ahead position. This is so that it has the correct amount of free movement for the steering wheel left, and right turns. once fitted the locking device is removed. 

John.

[PRT68]

Is the brake light switch ok? This played up on my Prius and cruise control failed. New switch cured it.