Horn Failure/Steering Wheel Switch Unit Failure

Horn Failure/steering Wheel Switch Unit Failure:

Fault symptoms
The horn does not work and there is no diagnostic trouble code.

Some of the steering wheel control buttons do not work, no diagnostic trouble code.

Diagnostic help
The horn button can be read with the diagnostics tool.

The horn output can be activated with the diagnostics tool.

Check wiring harness.
Jiggle the wiring harness at several points and in different directions to reveal intermittent breaks and short-circuits in the leads.

Observe the multimeter, test lamp or diagnostic instrument during the test.