I wrote a more detailed post on this which got lost due to a browser crash, so I'm not bothered typing it all again. :)

However, I recently got my first magna, a TF wagon Altera, with cruise. Cruise didn't work when I got it (i noticed this on test drive) cruise button lights when pressed, but can't engage when move stalk down.

I did the diagnostic by hooking an LED across a couple of pins in the OBD (which isn't OBD) port and the codes were ok. I then pulled the horn cover (mine doesn't have airbag) and the steering column cover and found both ends of the clock spring. Using a multimeter I determined that 1 of the 5 wires that go through the clock spring wasn't conductive.

1 wire used for horn (ground is other half)
2 wires unused (I'm guessing these would normally be for airbag?)
2 wires for cruise (difference resistance values used for each switch position)

Anyway, not wanting to find, buy and fit a clock spring, I carefully released and swapped the pins around between the failed cruise wire and one of the unused ones, both inside the steering wheel and on the steering column, so both ends match.

Now works 100%, and I'm happy.

Not a recommended fix if your car has airbag obviously, those wires would be used. But for me I don't consider it unsafe; no one will swap and airbag wheel into a car that doesn't have it surely...

Next time I do such things, I'll take pics.

I reckon that's a good cheap fix. Thanks for the tip.