2004 xkr
after driving for a distance the the amber light comes on and says ck rear lights and cruise unavailable Have replaced switch cleaned contacts worked for a very short period of time a day or two but back to amber light. when you turn off car and start again it is gone after it does system check but comes back after a several miles is there a sensor that could be bad or what else can I do

 

It is very likely the brake switch, off of a peg on the brake pedal. There are many threads on this forum. Did you mean you already replaced it? If so, triple check the "trigger" part of the switch. There is a sliding mechanism, on some form of plastic ratchet. The best would be to figure this out on the old switch, off the car. Some online pictures show this clearly as well. It should probably be extended all the way first, then have the brake pedal peg set the ratchet to wherever it is going to slide. Hard to explain...

Best of luck, keep us posted.

 

Sounds like the brake light switch to me too. I replaced mine earlier this year and my similar troubles went away.

 

Same with me. At first the fault would come on and, after a shut down, all would be well. As time passes(and the birds sang) it began to happen more often. Bit the bullet and am replacing the brake switch.
Film at 11.

 

What is the voltage across the battery terminals with the ignition in the off position?

 

The cruise depends upon the brake circuit to sense when to disconnect and if there's a problem in that circuit of any kind (a short for example) it wouldn't activate as it would think you've applied the brakes. A defective ABS sensor will also disable the cruise as would a problem with a directional stability circuit as they are all tied together and interdependent.

I'm in agreement with the previous posters that a faulty brake switch would be my first target.

 

But a failing battery is also a known culprit and even easier to check . . . hence the post from NBCat. Not saying it's one or tuther, just what's known and a simple check.

Best wishes,

Ken

 

On my 05 this light was on and it was a rear side marker light socket. So check ALL the rear lights first. If OK then I would suspect a faulty brake switch installation.