In all other cases, there appeared to have been some other indication of a problem, in addition to the cruise control not working. But you have indicated that the brake light switch CAN operate the brake lights properly and still have adverse effects on other items. So replacing the brake light switch is the first logical and inexpensive step.

 

That is correct. The brake light switch has solved the wing and ESP/ BAS light for several of us. Hope it is helpful for you, but I can not be certain.
There are wiring diagrams in the service manual. You may want to look them over. click here to download if you need one click: 2005 NA and SRT6 service manual

Thank you to 180 and Timelord

 

If all else fails, stick one of those cigarette-lighter voltmeters in and watch it when you drive. If voltage varies a lot, I'd suspect alternator or battery.
If fact, I replace my battery at four years. Your battery is your electrical system's filter - and these car's various modules seem to be REAL fussy about how well the B+ feed is filtered.

 

The brake switch is in the Cruise Control circuit, touch the brakes and CC switches off immediately. There are more contacts than just contacts to the brake lights on the brake switch.

 

Well, the good new is I was able to get all of the under dash panels off, replace the brake switch and get it all back together (with no screw left over) and everything is working correctly, except the cruise control. At least I know it's not the brake light switch.
Re: Battery, I installed an inexpensive after market TPM System, as there wasn't even a TPMS light showing on dash at start up. The unit plugs in to the cigarette lighter shows voltage 14.2 tor so while driving without much variance. Battery is less than 6 months old.
Thanks for all the help, but we will probably just live without Cruise Control unless something else pops up. We don't expect to take it on long trips anyway, it's my wife run around town car.

 

Does the TPMS warning light go on when you first turn the key to start and all the instruments lights turn on as a test just before starting the engine? It is located on the left side at the top of the other warning lights. If it's not showing then a previous owner disengaged it. It will never light if the GY/YL wire in the overhead cabin light has been moved from it's number two position on the connector to the blank number 6 position. See post #3 click here

 

The light does not ever go on, so I suspect you are right, it has been disabled. I'm not worried about it as the new TPM System I have works fine. Unless, having the original TPM System disabled, could in some way cause the cruise control to not function. Then it might be worth investigating.

 

Any codes show up, the CELdoes not have to be on to Have a code set.
Speed sensor failures can cause this problem.
There will be methods in the Service Manual for checking the system.

 

No, this has absolutely nothing to do with your CC not working. Totally separate system with no interconnectivity.

 

Thanks for the precise and specific response!
That was my impression after reading all of the posts requesting info on disableing the TPMS with no mention of potential side effects!

 

No scanner so no codes. Not sure what CEL stands for - Check Engine Light?
I will research the speed sensor question.

 

Bingo ........

 

I’m having exact same CC issue… It holds under 70 mph but nothing above… Has anyone found a solution…?