It seems as though we're on the same track here. However, you've gotten into the cruise control issue a lot more deeply than I have. Electrical system troubleshooting wise. Even though ALL the bulbs had seemed fine anyway, I've only replaced the stop tail light bulbs with the longer lasting 1157LL bulbs but not the high mount tail (it seemed fine). I am also suspecting and have ordered the stop light brake switch. I'll hope it's why the cruise won't engage or work. The other possibilitity I had thought of is the cruise control steering wheel's stalk (switch). I can't imgaine the main ECM's going bad but it could I suppose.
Let me know what else that you have determined. Thanks.
Cruise control is typically disabled any time there is a brake light failure.
And you MUST use OEM or equivalent bulbs with equal or greater current draw, NO LEDs, unless you modify the bulb failure sensor. Oftentimes not even the LL, Long Life, bulbs will not "trip" the bulb failure sensor.
Driving around I sometimes see cars wherein the tail lights go slightly dimmer when the brakes lights come on. This is usually a sight of poor chasis ground connection, negative side battery return, at/from the dimming tail/brake light fixtures.
:chairshot: Looks like your myth on tail light bulbs interfering with the cruise control is debunked here. Take a look at this link. http://gdl-online.com/bulb.html