This thread is really helpful, but I'm still having a hard time diagnosing a cruise control problem.
I have a 2002 Focus SE auto sedan and the cruise suddenly quit working - no light on the dash comes on and nothing happens when I press the switch.
I do have LED brake light bulbs, high mount stop light bulbs and license plate light bulbs, but I'm pretty sure I used the cruise control after installing them with no problems. Data on this seems inconclusive
. (But perhaps I was wrong about it working as that is seeming like the most probable cause).
I wasn't able to get the diagnostic mode to work. When I turn the car on with the OFF button depressed the Cruise light on the dash comes on for the bulb test, but when I left go of it, nothing flashes and nothing flashes when I press the specified buttons either.
I tried removing the green switch and it came out really easily and then I couldn't get it to go back in (but I didn't have the trim panel removed either). I was thinking maybe the switch just came loose from the bracket and that is the problem.
I didn't have a jumper wire with small enough terminals, so I tried using a paper clip across the terminals and that didn't work - but it might not have had good contact.
I took the green switch in the house and verified it had continuity when the plunger was depressed and not when it wasn't.
I was going to try plugging the switch in with a clamp holding the plunger depressed, but when I tightened the clamp, it collapsed the switch (before it was stopping at about 1/2-inch out for the depressed position). I connected the switch and it fell out of the clamp, but I managed to manually depress the plunger by hand while driving, but it still didn't work. Looks like I need to buy a new switch either way, unless there is some way to take it apart and get it to ratchet back out.
At this point, I don't think it is the green brake switch (although it looks like I might be replacing it anyway). It could be the switch buttons, the module, or a wiring fault, or the LED's (which seems likely).
It was a pretty stupid idea if Ford ran the brake lights through the cruise control, but it looks like they probably did. At this point, replacing the LED's back to incandescents is probably the easiest way to see if I can get the cruise control working again. I don't want to splice the factory wiring to install resistors that cost almost as much as the bulbs. And I really hope the cruise will work with LED's in the 3rd brake light as I don't want to go back to 194's as 2/3rds of them were broken and it looks like it would be a real pain to install resistors on each light inside that housing.
If anyone has tips on why the diagnostic won't work, or how to restore the switch, or how likely LED tails are to cause this, I'd appreciate it.
Thanks in advance!