Steering wheel electrical

2004 300M.
None of the controls inthe steering wheel work, the radio controls, horn, cruise control. Anyone know what fuse, orwhat I need to do to get them working?

The best way to approach it is to troubleshoot it with a multimeter.

Check the voltages at the relay. It can be a power problem (to the relay coil and contact input), the control signal (from the steering wheel - the other side of the relay coil), or the voltage to the horns themselves (relay contact output), and then you can fine tune the problem from there.

You may have a clockspring problem.

When you use your remote to lock the car, do the horns sound? If so, then the problem is on the steering wheel control signal/clock spring side of the system. If the horns do not blow when locking using the remote, then the problem is in the relay itself, the power supply side, or in the output (contact) side of the relay.

http://images16.fotki.com/v31/photos/4/42816/4166363/horncircuit-vi.jpg

What kind of device is a clockspring?
a plug in module?

Clockspring is the "thingy" in the steering wheel that transfers electricity from the steering wheel controls and horn to the wiring system. It is made so you can turn the steering wheel and still keep a circuit. I don't know how easy or difficult it is to replace yourself, but I do know a few guys have done it themselves.

Thanks for the info, I had the clockspring replaced, and now everything works.

Thanks for the info, I had the clockspring replaced, and now everything works.

You're welcome. Glad it all worked out for you.